for white upholstry I have slight yellowing,what would work to get it white again ? thanks

I use 100% mineral spirit on mine works fine.

Gentle soapy water and MR Clean Magic Eraser. Target has a knock off sponge about the same. Without it you will never get in the tiny folds.

Agreed 100%...as long as the yellowing isn't really bad, and hasn't sat there forever! I used magic erasers the other day to detail a completely white interior. i had no clue it was supposed to be the white and BRIGHT! all i used was the eraser w/water. saop would add to it's power i'm sure.
a buddy of mine was using soft scrub bleach on his white interior...looked great! not sure what the long term effect is though as it's a fairly harsh cleaning agent. just my .02

A few denture cleaning tablets in warm water whitens yellowed fabrics. Test a small area first.

Cool...never heard of that before.

Boat Bling's Vinyl Sauce...this stuff is awesome, along with a Mr. Clean Magic Eraser it can't be beat!

http://boatbling.net/bbFrameset-1.htm