I spent all last night dyeing my clear pink/purple Starminx to black. It took me close to an hour to complete dismissible all of the parts, turns out that there are 122 screws in the thing. 12 for the core, 30 for the outer edges, 60 for the acute triangles "star parts", and 20 for the corners. I did not want to soak the screws so I unscrewed all of the pieces. If I knew it was going to take as long as it did to dissemble and reassemble (about 3 hours all together) I probably would have soaked the screws too .

I used 400ml of water 200ml of acetone and 30ish grams of rit dye, and I'm pretty happy with the results. In good lighting it looks a little more brown then black, but I'm okay with that because the lighting in my house isn't great anyway . If you hold one piece up to a light you can almost see through it, It kind of reminds me of a brown beer bottle.

You used a 33% solution of acetone - seems a bit high. How long did you soak the pieces for?

I soaked it for 15 minutes. I've now resticked it and have spent about an hour playing with it and it seems almost exactly the same.