Eraser Mod is an alternative to delidding the CPU package. It works by putting an eraser piece in the hole behind the CPU, what this makes is it increases the pressure applied to the package evenly, and mitigates the old dried thermal compound inside the CPU package. It may seem like increasing the pressure on the CPU package may tire the motherboard and break the traces, but this "fix" is actually official, some models of PS3 already come with a plastic piece attached into the hole, so even Sony thinks this is fine to do. The only required tools are a screwdriver to open the PS3, and some sort of knife to cut the eraser into the shape. You can actually use any kind of eraser, soft or hard, contrary to what is said in the original forum thread. I have tested both. The model I used here is a CECHL.