Using petrol as a solvent is a mugs game at the best of times, without the price hike.It’d be cheaper to buy a new stove than waste any petrol at the moment mate!
Paraffin is what we used to soak engine parts and gunked up threads. Can be reused, still fairly cheap at about £35 for 16ltr.
I’d put a can in an old ice cream tub or beach bucket, stand the pipe up and get the drill brush in there so it’s constantly being dipped.