All it takes is a little water. If you're cleaning your guns regularly that shouldn't be a problem.the fouling could build up on the excess threads of the nipple and make it hard -maybe impossible- to remove until that fouling is dissolved somehow.
Either instance might result in damage to the threads of the cylinder, and would promote a need to have a suitable tap to clean the threads of the cylinder's nipple channel if using nipples with shorter threads before the proper parts can be used again..