on pottery —
Sometimes — perhaps often — we collectors and dealers come across grease pencil marks on our studio pieces. This is the simplest method I have come across for removing them — WD 40. Doesn’t always give perfect results particularly on stoneware due to that clay’s coarseness but enough to erase the marking as an in your face feature.
I don’t use it on glazed surfaces as usually plain dish soap detergent, a bristle scrub brush and warm water will do the trick. A word of caution — wipe, swipe — don’t rub — the marks should be just floating on the surface and that’s what you want to do — dissolve and float the marks away. You don’t want to push the grease mark into the pot! Use one cotton puff with a spot of WD, swipe and discard.
Once it is off or as best you can do, give the spot a quick squirt of straight detergent and circular brush with your bristle scrub. You want to clean up the WD and get it off the base. Rinse thoroughly. If you have been diligent, the detergent with the scrub will often lift even a stubborn grease mark. It will be sweet as a nut or a Mexican Jorge Wilmot cat
If you have any doubts about using this method on a Museum quality or rare piece than don’t do it. Check with a professional conservator. Sometimes we just have to live with them. I have a Robin Hopper vase with a stuck on fluorescent price tag.
Robin, I’m sure would like that — especially the price. I could probably take it off but what the heck it keeps me honest. These marks are ubiquitous on thrift shop finds — often a good way of knowing provenance.
For sticker marks particularly on glazed surfaces I use methyl hydrate or Varsol when detergent and water don’t do the trick. For some reason, Methyl hydrate and Varsol each work on some sticker residues and not others. I usually use the methyl hydrate first before going for the jugular. Cotton balls again and much more caution.