Ultrasonic won't touch that. You need to either scrape them off carefully with the back of an X-Acto or utility knife, or use a magic eraser.Would an ultrasonic be able to clean these marks? I already gave 'em a good scrubbing w/ a toothbrush+Dawn, i'm satisfied that the hooker juice was cleaned off, but these rack-check marks are some of the most vicious that I've ever seen. Any tips, or should I just invest in a ultrasonic cleaner?
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BTW I hope everyone understands that magic erasers work because they are abrasive and actually remove material from whatever they're scrubbing ... in other words, they take rack-check marks off because they are basically very fine-grit sandpaper. GO EASY with the pressure or you will take off too much of the chip.