Whitening toothpaste? It contains a mild abrasive to remove light dirt from teeth enamel. Plus a very mild bleaching agent that is not aggressive. Suitable for lightly tanned Macs?

Thinking chemically, we need an oxidising agent that causes less wear than bleach or ammonia. Any agent will probably weaken the case on the outside (10% penetration) but we can't afford to weaken the inside. Any suggestions for a long chain oxidiser that will get tied up by ABS plus filler?