After evaluateing the muffler I find some rusted spots not soft and I want to
apply antirust solvent maybe repaint the thing..no muffler problems just preventative..Any suggestions ?

 

Save your money, mufflers only last so long, and you can pick up a replacement one for $20-30. Just my .02

 

Barbeque paint (or header paint) is high-temp.

 

What I am driving at is the pipes are rusting a little the muffler is fine..I just want a little touch up .There are alot of welds no sence in dropping the whole muffler system.
Besides she passed the smog inspect two times in 3 years good reading..thanks for the paint tip.