I redyed the carpet in one of my other cars. The really important thing is that it's super clean. I'd recommend taking it to a car wash with high pressure wands. Spray the carpet down with strong degreaser and spray it all off. It doesn't hurt to hand scrub the carpet with lacquer thinner either, but you only have have to lightly wipe it off really. I used SEM I think when I did mine and I put it in my siphon feed gun. When you finished and it's dry, brush it with a soft bristle brush like a hair brush to get the thread to stop sticking to each other. It gives it a softer look and gets rid of any clumps.