In order to preserve shell habitats and to keep all good areas from being "shelled out":

*I will replace to their former position all objects turned or moved to look for shells
*I will always leave every shelling spot as undisturbed as possible. I do realize that
  the balance of nature is delicate and everything depends upon other kinds of life
  for its existence
*I will not collect live egg cases unless they are to be used for study and in that
  case I will take only small quantities
*I will not take "baby" shells unless they are to be used for scientific study. I do
  understand that juvenile shell are not considered to be good specimens, have no
  value, and are not proper exchange material
*I will not be guilty of cleaning out  a "colony" of shells, or of collecting every living
  thing I find
*I will  take only the live shells needed for my collection and for exchanges  at the
*I will not collect mollusks (the living shells) which are in bad condition, such as
  those with broken spires, badly chipped lips, bad growth flaws, or erosion
  (these unlovely creatures can propagate the species and produce
  progeny that are of choice quality)
*I will practice and promote these good conservation rules in every way possible
  to assure that further generations may still have the shells of mollusks, as well as
  other wildlife, to study and enjoy

Reference : Concologists of America      
                 Reefkeeping magazine    
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