Hi Kai,

If the chips are not BGA (which is to say if the leads are still accessible on the perimeter of the package), you can still ground all of the leads before doing anything fairly easily. Just cut an aperature in a small piece of shim stock, 10 mils thick or less, and attach a lead and clip for grounding. The aperature should be a friction fit to the leads on the package body, but be careful that the edges don't bend up and bind against any verticle portion of the leads. Otherwise you won't be able to get it off without damaging leads. Just keep it a very loose friction fit, just barely tight enough to make the slightest contact. (It doesn't have to be a strong contact. Remember that shoe and wrist straps usually incorporate a 10 Mohm series resistance.) Grounding the leads is the sure-fire way to protect the chip from ESD damage, whatever process you use to remove the stamp. And if you are going to use your mill, or a Dremel tool (with emory cloth or whatever), I'll keep my fingers crossed for you. Keep a light touch, and good luck.

Joe