stains on plastic tub from caulking

[apointer]

restoring a home we repoed. The tenant put great gobs of caulk on the tub around the rim. I have removed the caulk but there is an orange stain where it was. So far, bleach, mold killer, caulk remover, and 409 have not touched this stain. Plastic tub.
Any Ideas ???

[Koiflowers]

I had a tub stained with red iron (well problems -- had to drill a new well). Absolutely nothing on the planet would remove these horrible stains. I even bought a one-piece tub and surround only to find it wouldn't go through the door.

I found another site that said to buy Super Clean in the big purple gallon bottle in automotive section of Walmart. I was leery, because I too had tried everything on the planet and nothing would even touch these stains not even TSP, magic eraser, Bartender's Friend, CLR, straight bleach, or Iron Out -- 8 YEARS OF USELESS SCRUBBING makes you pretty hesitant to try yet another product.

We tried it night before last, and every stain came off with lots of scrubbing with full strength Super Clean and the scotchbright side of the sponge. The original post said it was for cleaning tubs that had yellowed. I'm speechless and I keep looking in that bathroom in absolute delight that the red streaks from hell are finally history.

$6.95 per gallon and worth every penny. I'm going to tackle red streaks in toilet soon.