I've cleaned late-ish MB wheels recently (E320) and found the stick-on wheel weights to be extremely frustrating and time consuming to remove. The lead (?) weights are stuck on with foam which is coated with adhesive on both sides. The only way to remove the weights without wheel damage is by carefully using a hammer and screwdriver (or chisel). The pliers that're normally used to remove the other type of wheel weights (that hook over the rim), just won't grab the stick-ons and if you try...