Indiscriminate collecting of cave formations (speleothems) is grounds for death without due process. This form of vandalism can never be repaired. Even broken speleothems should not be collected but placed to the side of the passage where they will be safe. Such formations can provide valuable information to geologists studying the cave. The only exception to collecting formations is in caves being destroyed by quarrying or road work. However, such caves can be highly dangerous and should only be visited by experienced cavers with the permission of the contractor.
Never collect fauna (bats, salamanders, fish, etc.) unless you are associated
with a worthy scientific endeavor. Collecting can, and has, wiped out colonies
of rare and interesting cave animals. It is hard enough for them to live
as it is without you picking on them. Spent carbide is particularly destructive
to water life. Hibernating bats must not be disturbed; many die when they
are awakened.