I use scotch brite, great for cleaning weapons and I discovered great on exhaust pipes.
Whenever I go to stores its one for the cleaning kit, one for the bike
as it says online:
3M Scotch-Brite™ Cleaning Pad (no.96) is a flexible yet long-lasting pad ideal for weapon cleaning purposes. Will easily handle both light and heavy duty dirt and carbon deposits. Out performs wire brushes, steel wool and other non-woven materials. Open construction won't rust and will absorb many time its own weight in water. An essential addition to your personal weapon cleaning kit. Also great for cleaning mess tins and metal mugs in the field