It's been discussed here before re using a dab of oil to obscure slab scratches when photographing coins but I've never seen before and after photos. Since I'm shooting coins today and I got some pretty dramatic before and after shots of a scratched slab, I thought y'all might like to see how much better it can appear. The coin is an 1832 half dime in AU-50. The oil is a dab of olive oil (mineral oil is also good) rubbed somewhat aggressively into the surface of the slab, more or less perpendicular to the scratches. I only use on the surface directly over the coin because I don't want the oil to remain in the other nooks and crannies of the slab. You want the oil to get down into the bottom of the scratch and also overcome any surface tension that might prevent the oil from wetting the sides and bottom of the scratch. Dry with a paper towel or other relatively lint-free cloth. You want to get the oil off the unscratched surface but not remove it from the scratch. After photographing, remove as much of the oil as you can with a cloth. These photos were taken within a few minutes of each other with no changes to aperture, focus, speed, or lighting so all you see is the difference caused by the oil.
Yes that's very cool trick to remove any artifacts on a slab. However years ago I owned a 95 M miata fun car drop top and go. However if you ever owned a boat or a rag top the plastic windows get straches from everything! Sunlight is a real killer of plastic windows. I used a product called Novus in 3 strengths did a great job on my boat ,car and coin slabs to remover straches. Your trick is great for the quick fix to shoot a good image.
A coda to my original post. I used olive oil on the slab in question because the mineral oil was out in the shop and I'm lazy. But I would not recommend olive oil because it is both organic snd acidic. Little bits of it remaining on the slab could go rancid and yellow. And the acid might damage the plastic. Can't say that's true but better safe than sorry.
I will admit that I wish I had thought of trying that on the 1943 NF dime I had.....it was in a newer NGC holder, but for some reason right over the face the slab was like hair line straches making the face look milky over the toned coin back ground. In hand one could definitely see that the coin was perfect...
