We've all head this method before, but the solution dissolves the caps. But what if you would fill the cap with some inert ingredient like flour, put a few drops of solution in the cap, and cap it after that?
Would there be any negative side effects?
I'm not sure what you're doing.
Caps will dissolve from contact with propylene glycol. Once it evaporates it won't do that. So you could dissolve it, add to flour, let dry, then cap them, but I don't know why you'd want to.