Depends on how bad it is.
For regular soot that is cleaned off regularly and most chrome: P21s soap, or mothers/blue magic etc, P21 multisurface finish restorer for more stubburn spots. The drill tools can make this go quicker, but they tend to sling. Eagle 1 never dull works well on the exterior.
For heavier baked on stuff on stainless: get rid of soot first with orange oil degreaser or p21 soap, Let soak with some citrus bbq grill cleaner, clean off, polish with the P21 multisurface finish restorer with some 0000 steel wool or a green scrub pad. I also have some supplies I used to polish a seat of SS headers if all else fails. Be careful with getting too agressive with chrome since its a plating.