Replying to Alternatives to Dyeing Boots

So, recently I attempted to dye my ancient Nordica boots, but both the shells and heel pieces would not take the dye. I may have put in too little dye for too much water in with the shells, but they did not change color at all. I was wondering if there were any other methods of changing the sppearance of boots. I know that spray paint would chip right off, but I was wondering about plastidip. Arethere any other methods you guys have tried? +k and whatnot