How to remove surface rust w/o abrasives?
So I am finally getting around to registering our vehicles down in CA since moving from WA. Cue the smog check challenges.
Unfortunately the catalytic converter on the van has enough surface rust that the codes printed in to the metal are barely visible. Since it isn't the factory cat, the smog shop is is required to use those numbers/letters to verify that the aftermarket cat is appropriate for the vehicle. I've worked at it with some fine sandpaper, WD-40 and PB Blaster and have been able to discern 80% of the characters, but the sanding is gradually making everything fainter/harder to read.
Does anybody have any suggestions for removing surface rust w/o using an abrasive that will sand down the metal and make the letters unreadable? Or any other tips for how to handle this? I'd love to avoid having to buy a new cat to resolve this...
2003 E250 Self-Built Van
Santa Cruz, CA