If you are looking for something like a penatrant to undo bolts etc and they can handle a little change of colour

. Look for something called diepenatrant . It is used to detect cracks etc , used in two parts . Spray on penatrant , let soak in and wipe off . then spray with a fluro reactor and any imperfrctions show up .
Just need the die half off it , worms its way into almost anything . The bummer is its usually bright red .
Chris