When I got it it was a wreck. I tried elongating the springs like Pestvic does but it wasn't worth it and the springs got bent out of shape too easily. So I took a dozen (quite literally, a Megaminx has 12 sides
) M&G retractable pens (I'll get a pic up if you need it) and replaced it with those springs. I also sanded the tiles with fine sandpaper, and then polished it with plain white paper so that the tiles have some grip on them (David Gugl's idea). Lube? I lubed it with copious amounts of CRC (there are plenty of white stains on the inside) and Maru. I don't even need to lube it nowadays. I didn't sand any pieces, it was just too tedious and I like it the way it is. And then I solve it a lot. Don't forget to even the tensions on every side. The only cons of it is it is too slippery, and I might accidentally turn unwanted faces, and the tiles are still quite slippery, despite the sanded tiles helping, but not much.