My tuppence worth.
Dettol is awesome at stripping plastic minis. But you have to scrub them in the solution, which WILL give you chemical burns. Wear rubber gloves, not latex ones, as they will dissolve also. I keep my dettol in an airtight jar, and just use an old sieve to strain out the gunk that builds up. It wont dissolve solvent based paints and varnishes so avoid buying stuff that looks like its been daubed in humbrols.
I find an hour is all thats needed before the paint starts to come off easily, overnight and it comes off very Very easily. And it does weaken glue joints.
For metal minis, I just drop them in a jar of whateveres to hand, nitromorse, white spirit, brake fluid etc, and give it a good scrub after an hour or so.
Back in the 90's I left a few plastic marines in turps overnight. They went all floppy. Dont do that!