Usually when I use a metal cleaner/polish I don't bother washing the towel. I'll use another clean spot on it for another application at a later time and then just toss it out. Bulk packs of terry towels are pretty cheap so I don't waste my time washing them and risk getting residue in the washer. I also use Wal-Mart , Sams, Costco or other cheap MF's for things like wheels and jambs that also get tossed when filthy.
If I'm ever concerned about a residue in the washer I'll use some APC to wipe it out and then run hot water through it to make sure it rinses clean.
You can usually see a film either on the walls of the wash tub (depending on color) or sometimes a film on the top of the clear water you're trying to clean it out with. I'd say the hot water cycle probably got most of the residue out but if you're concerned I'd do an APC wipe down of the wash tub, run at least one cycle to rinse it out, and then rewash your good MF's using ~1/2 cup vinegar in the first of two rinse cycles. My rule of thumb is to run rinse cycles until the rinse water shows no signs of soap (suds). With a good MF detergent, I use Micro-Restore, the second rinse cycle might be overkill, but it makes me feel better and my WW's never have an absorption problem.
I'd probably be more concerned with the dryer because I don't know that running it for 10 minutes would do a whole lot to get rid of any residue. I often do a quick wipe with IPA to make sure there isn't a lot of fabric softener sheet residue in our dryer, and it only take a few minutes to give it a good wipe down inside.
Or you can just test a couple of your good towels out and see how they work.... do they still absorb well and not streak or smear? If so you're most likely good to go.
