For my LiFePO4 cell management I am flashing a bunch of ATTiny85's with different millivolt correction factors to account for the 5% tolerance of the voltage divider. So I need to label them -50, +50, +100, etc.
All the colored felt-tip pens I have tried make dingy lines that are hard to read, very similar to the existing chip markings! Scratching works but can't be erased. Sticky label/rubber cement is messy and will probably fall off over time. Velcro attachments seem like tremendous overkill.
I don't have any nail polish but will buy an assortment of colors if that is the best solution. I'd really like to write on them; is there some fine-point erasable grease pencil designed for IC marking?