The exchange is a very interesting source for expanding quantitatively a collection and the most profitable from an economic point of view since all malacologists can easily get large numbers of duplicated shells coming from their own areas and probably they may be willing to exchange with ours. In this regard I recommend that you must take care of saving any shell in spite being very common. Shells which seem to be certainly common or abundant in your area could become rare for another collectors living on the other side of Earth.
There are many ways of making a shells trade. Actually nothing is written about it so everyone is free to arrange a shells exchange with its own rules as long as obviously, both collectors involved agree with the particular terms of the trade. However, let me give you some guidelines about the exchange ethics based on my experience gained over the last few years. This could be considered as a sort of "conduct code of the shells exchanger":
An updated exchange list must be always ready. The information displayed in this list should be as complete as possible (see paragraph on labelling above)
If you're the one who has the initiative to contact another collector, you'll be the first to send the requested shells, unless there is an agreement to do otherwise
Never send shells which the other collector has not asked for or at least if you're going to include some extra shells not included in the exchange agreement give this information before making shipment
You should warn the other malacologist on the quality of the shells you're submitting, especially if some are damaged, and on the number of specimens of each species you will send. Here you will find some categories that malacologists often use to determine the quality of shells (although I have always thought that this issue is very subjective and really everyone attribute the quality degree in an own way):
A perfect specimen, completely adult, coloring normal, without damages, breaks or visible defects. Gastropods should have a perfect spiral shape, having intact the first coils and have no broken spines or chips on the outer lip. Bivalve shells must have both valves. The specimen should not have an oil or paraffin excess and be perfectly clean inside and out.
Fine (F) -
An adult with a small defect or some slight growth mark. For example, a Fine Conidae or a Volutidae shell can have a small notch in the lip, or some roughness, a Fine Muricidae or Spondylidae can have some briefly broken spines. Shell repairs are not allowed. The shell must have the original color and brightness and well clean inside and out. Within this category subcategories can be made as the magnitude of the damage (F for the most notable damages; F+ for slight damages, F++ for very slight damages and even F+++ for shells almost reaching "Gem" condition, i.e. more + signs mean that shell is closer to the "Gem" condition).
An acceptable specimen with some damages (growth marks, broken spines, lost some initial spiral, chips on the lip). The shells can be subadults but must display all the characteristics of the species. Well cleaned inside and long enough outside.
Poor (or Beach) -
Eroded specimen with obvious damages (broken spines, lost coils, holes and so on) due to exposure to climate (found on the beach) or handling. These are very few valuable shells unless they involve very rare species difficult to get in a better condition.
Other indications that frequently find interesting are:
Immature shells that could be treated as "Gem" in the case of those species that differ greatly in their adult status as Cypraea or Strombus.
With operculum which concerns gastropods. When the quality given to the shell is "Gem" the operculum must be the original of the sampled specimen.
Monstrous or deformed specimen either by defects in growth, colouring or even due to the place of collection. Some of these shells reach really high prices since they are much more scarce than the standard rate of the species.
You must know that sometimes the exchanges are not carried out species by species, since the value of a Gem 20cm size rare marine shell sampled at 500m deep can not be the same as another Fine 2cm size common marine shell collected at a few centimeters deep. Then it is necessary to establish an economic value to your shells (there are Websites and establishments specialized in giving prices to many species of mollusks, although no one better than oneself to know what is the value of the own sampled shells). Therefore, never achieved rare shells in exchange for common shells. Too often one may see in trade lists of other collectors a warning as follows: "not supported changing one €100 shell by 50 shells valued at €2 each "
The first shell exchange with another malacologist is always the hardest by natural distrust of the relationship between two people who are not well known. It is advisable to send by e-mail a photo of the shells in the package previously to put it in the post office and may even be good sending by e-mail a scanned copy of the postal receipt. Unfortunately there are many scammers and fraudsters in the world (in fact I have a list with names of alleged scammer malacologists. If you're interested I can send you this list by e-mail. Please do understand that the sensitivity of this information prevents me from a public disclosure on this Site).
Meet the malacologists ethical code available on this Website.
Any malacological magazine or the Web can be useful sources to find good candidates for making shell exchanges (have a look at my links section).
Collectors do not consider very seriously the issue of exchange at first. In fact many of us have not discovered the exchange by our own initiative but by chance. Once you discover the exchange world when collecting shells you always try to sample some extra ones to get an exchange stock. With regard to how store such duplicated specimens, you may check the final section of this page (exhibition and conservation) where I talk about the type of furniture and cabinets more useful to store shells. However I must clarify that you should not give the same store treatment to your stock of duplicated and your collection because the shells for exchange are much more handled and so they should be much more accessible. In this sense a good way to save your duplicated shells is by using plastic boxes easily gained in the stores like "Eurochina". I show some of which I used until I was able to buy some furniture with drawers.
Now I have got nice cabinets as you can see below. I spent many years looking for these kind of furniture and a lot of saved money. It was difficult because there are no local companies in my town so I needed to resort to other Spanish companies far away home. Later I offer you information about purchasing products such as the photographs.
I do not want to finish this section without giving some basic rules to arrange a shells package for exchange.
First of all you must find a box with an appropriate size according to the amount of shells to be sent. The material which the package is made of must be both lightweight and resistant (cardboard, plastic, polystyrene or porexpan are the most commonly used; need not be purchased containers but any domestic container). The box must be hard because you never know which treatment during transport will be given; you have to think that as farther away you send that package better you must make sure that the shells inside will not suffer any mishap. The box must be light because the postage rates depending on the weight of the package and often they are expensive especially when international shipments are involved. So I recommend you have a small weight at home that allows you to calculate the weight of your packages. Not necessarily has to be a precision weight so a simple weight cooking usually yields good results. Sometimes a difference of a few grams can make double the price of shipping (for example a package of 995gr with U.S. destination could cost you if you send from a Spanish post office €20.99, but that value will rise to €33.24 if your weight is 1005gr. This is because our postal service charges a fee for certain weights between 350 and 1000gr while other fees too much higher are charged for weights between 1001 and 2000gr. If you are interested in calculating the price for postal sendings through the Spanish postal company, click the following link: Postage expenses calculator.
There are other agencies in Spain to transport your packages but often offer rates even higher than the previous one. In addition the service of such companies is very limited and postal services to all countries are not available. Even that is the case of such companies that allow shipments from other countries to Spain but not otherwise. Anyway I have noticed some notable improvements in shipments by the Spanish postal company last years. Now everything seems to be much faster. As an example 10 years ago a package from Jaen to Malaga (200km away) used to take up even ten days but now it takes one or two days at most.
The second and most important matter at the respect of preparing a shells parcel is the way in which the shells are packaged. There are many "recipes" for packaging in fact virtually everyone make up their packages with a personal style. I can give you some basic tips that I use. Shells must be well protected from strokes or friction among them which depends greatly on the size of the shell. For small shells they must be placed in small tubes or capsules while shells from medium to large sizes should be carefully wrapped one by one with paper or plastic wrapping paper introducing the shells of the same species in a single MultiGrip bag (hermatically sealed bag). Sometimes you can choose to put shells into small boxes or small plastic containers filled with cottons (providing specimens of the same species in the same container). Only when we are sure about each single shell will be well protected we must introduce all the shells in the selected package. Then the hollow spaces of the pack have to be filled with some kind of packaging material such as cork or plastic shavings, cuts of paper, plastic bubbles, cotton, and so on...Hence shells will travel inside the package firmly subjected because no holes that allow shells to move and crash with each other and against the package during his trip exist. Finally you should wrap the container with a paper wrapper (with the help of packing tape) where the address of the sending and yours as the sender may be writen (do not forget that some problems with the packages often occur so you must facilitate the return of the package to your home).
Do not forget to attach to each shells into the parcel a label displaying full information about its collection data. You can also send the detailed collection data by e-mail. The Microsoft Excel sheets are an ideal format for this purpose.