How to make shells soft?

[paul monfils]

Not much chance of doing that I'm afraid.  You can soften bones by removing the calcium salts with acid or other chemicals, so that the flexible matrix is left.  But in shells the calcium salts are pretty much the whole deal.  There may be traces of proteinaceous material in among the calcium crystals, but 99% of the shell is made of calcium carbonate and sometimes lesser amounts of calcium phosphate.  So basically if you remove the calcium salts, the shell is GONE - dissolved!  Why did you want to soften them?  So you can drill them?  There are ways to do that.