cleaning exhaust soot

Is there a good way to clean the exhaust soot from the inside of the exhaust tips on my 71 Charger R/T? It has the original machine gun style exhaust tips with the red inside. It's been several years since they were rechromed and they're all black again. They're welded on so I can't remove them to clean.
Thanks

Plastic Pipe Cleaners that fit thru the holes and some Hot Wheels mag and wheel cleaner should do the trick.

Thanks for the reply. I was beginning to think I was the only person with dirty exhaust tips.
I'll give that a try. I've tried several other "kitchen cleaners" but done worked very well. I was also thinking of running a soft wire wheel on a drill motor for the inside of the tips until I got down to the painted part.
attaboy