I did once use black felt tip pen on a favourite black 'frilly' skirt - it had got some white spots on it due to splashing with Domestos liquid, which I used at that time to clean the cats' litter trays. It did sort of work (the white spots ended up dark brown rather than black!), but as it didn't look too bad I went on wearing the skirt for a while!
But you're fairly new here and still welcome, & it's mainly the same people on the other forum as on here so you'll still be welcome, & you'll like deano over there, he rescues dogs & is trying to get the doggy smell out of his car