FWIW, I've used Saphir White Novelys in the past on white sneakers. It actually works pretty great if the sneakers are truly white. I tried it on some off white sneakers once and it looked like crap so I quickly scrubbed it off. There isn't any sort of ingredient list on the bottle, but I don't think it has any bleach. I'm not sure about your GATs but if they aren't true white I would not recommend trying it.