cleaning soft plastic figures.

I have washed the figures in detergent and then soak in white vinegar.

Re the flash, I have heard that you can hold the figure close to a soldering iron to melt the flash but you obviously have to check you don't lose thinner bits like spears and swords!  I have also moved the figures quickly through a candle flame, shielding vulnerable parts of the figure between thumb and forefinger!

Simon

A drop of detergent in a cereal bowl full of cool water will do for scrubbing with a soft toothbrush. I've never used vinegar as a stripper, but it's worth a try. I usually clear the flash with a sharp pointed craft knife, but you have to have a very sharp edge to avoid the fuzziness. I have used a hot needle instead. If you don't have a soldering tool for that, a candle flame works. Put the needle in a piece of cork, and shield the flame so you don't go blind temporarily. The others are quite right, heat can go badly fast. Be very careful.
Emery boards are useful for fine sanding on resin. Needle files as well.

No naked flames... Something to do with my parole officer.

Blades are fine though.

Heat works well, however the fumes are probably not good for your health.
If you decide to go for heat, I would use either a piece of wire heated in a candle, or a soldering iron with a fine tip.

Other than that, blades seem to be the only option. I would try a variety of shapes and varying degrees of sharpness (very sharp is not always best), maybe you find something that works for you.