I used to work in an automotive A/C shop and the Lysol thing is what we did for the musty smell prople complained about.

Put the unit in recirc and shoot it right into fans intake.

Never heard of one catching on fire from this, but since propane is the propellent used these days I wouldn't discount the possibility either.

you might want to know where a fire extinguisher is, just to be on the safe side.