In desperation a time or two, I have tried to soak diaphragms in various substances. Never have gotten a stiff one to limber up yet. Sometimes, but pretty rarely, if they are just starting to become little bit stiff, soaking them overnight in regular gas/oil mix can get them limbered up enough to run, but it is always better to replace them anyway. I'm talking about getting one more run out of a weedeater or something like that for the "band aid" measures...

AV8TOR