I took a pair of pliers to the grinder and now they do not leave marks.
Also have try printing labels, looks good but too time consuming. Tried many pens, I find the best one is made by Sanford. Its called the Uni-ball delux micro. This is a very fine tip and it dries relatively quick. Its claim to fame is that it is permanent and cannot be altered on a cheque. These cost about $8.00 for a pack of three at staples.
For what it is worth too much info on 2X2 is not good. Values change and sometimes grading is not right. Everyone has off days.
Info year and variety, and I catalogue using coin collecting software so I write serial number on back of 2X2