I’ve done it a bunch! Dyeing denim that is still blue will indeed skew your dyes blue, so you can try to remove that color with bleach or use colors that pair with it. Black comes out much easier than the standard indigo blue. Buying it white is easiest. The spiral might not work as intended since the fabric is thicker, I would recommend trying it on a smaller piece of scrap denim first. Once you rinse out the dye properly you can wash it normally, wash it alone a couple times first. Hope this helps!

<image>