I would suggest using sandpaper instead. Even though strippers like interstrip 299 say they do not harn the polyester resins they do soften it to a certain degree and the foil surfaces are not that large. Use fresh paper and change often and you will have no trouble...You can even use wet 320 if dust is an issue for you.
as a painter i use strippers all the time and there are some strippers that are citris based that would work well without damaging the foil......called citris-strip, most are orange based and are also easy on the skin. any paint store would stock these, like a sherwin-williams.i would just use sandpaper though.