Here are two coins that I find worrisome. The Trajan as is suffering from bronze disease, and I suspect that it's been painted and waxed. Since this photo was taken, I've soaked the coin in distilled water and removed much of the BD. The sestertius of Gordian III seems waxed to me, but I'm afraid of removing the wax for fear of damaging the patina. Marc: in another thread, you mentioned using a combination of benzine and acetone. How exactly is this done, and do you think these coins would benefit from it?
The Trajan is probably smoothed, or if not, has some crappy surfaces. The Gordian appears original from here, but could prove to be lightly smoothed in hand.
Bill, if a coin's been smoothed, I assume the smoothing would cut through the patina and expose the naked bronze. Then I assume the "restorer" would want to paint the coin to cover the smoothing. Is this accurate?
It depends on the amount of smoothing and thickness of patina. Effectively when you clean a coin the mechanical action will smooth it to an extent as well. You are right though. Massive smoothing on a thin patina will strip the patine off the coin, (or make it so ugly as you wish you removed it anyway). I never really mind smoothing, since its just taking a flat field and making it flat again. I only dislike it when its then fake patinated. Of course, tooling is an anathmea.
In the catalog descriptions, the term "smoothing" is frequently abused in order to avoid the terms "tooling" or "re-cutting". In Germany, restorers are equating "smoothing" with cleaning since smoothing is the best way of describing the procedure of exposing an object because it is performed by ablating oxides or sinter residues layer after layer. Virtually every object from ancient times are subjected to this "smoothing" (or cleaning) process. If the former epidermis of the object, which is for bronzes equivalent to the cuprite layer, is not penetrated, this kind of "smoothing" (or cleaning) is absolutely legitimate. Despite to "tooling" or "detail re-cutting", during "smoothing", the cleaner guides his tool in parallel to the coin's surface instead of cutting perpendicularly to the surface into the metal. "Smoothing" is exposing an object whereas "tooling" or "detail re-cutting" are forging it. Of course "smoothing" (or cleaning) should not only focus on exposing the object. It should also consider the aesthetic appeal. A professional, skillful cleaner knows when to stop ablating oxides and sinter residues even before the former epidermis is reached in order to avoid a spotty appearance or surfaces becoming rough.
Do not mix those fluids! Just put the coins one night in benzine and one night in a separate bowl in acetone. Purchase a pair of acetone persistent gloves. It does not matter if you come in touch with these solvents once but you should not exaggerate it. Do not dispose the fluids in the waste water. Absorb them with toilet paper, the fluids will soon evaporate. Don't worry, both fluids do not damage patina! All my bronzes have been at least for some day in these fluids. If something will flake off or corrosion pits will become visible, then this is the clear proof that you have been duped and you should not go to the dealer you purchased the bronzes twice.
Maybe, not! You will only no it after you stripped the "grease patina". Maybe, somebody wanted to conceal spots with bronze disease. Even then, it is better to remove the grease since it might be necessary to treat the bronze disease again.
Maybe, I have to correct myself. I meant with benzine something that you might call in English "white spirit": http://en.wikipedia.org/wiki/White_spirit In Germany, we have the so-called "Waschbenzin", which literally means "washing benzine". I am using this for removing wax. As far as I understand the sheets of hazards, you should avoid dermal contact and in case this happens, you should diligently wash the affected part of the body.
In Germany, you get both acetone and white spirit in either drugstores or construction markets. I am sorry, sometimes, my English might be poor. Hopefully, I will improve.
Your English is certainly better than that of many Americans. Anyway, we have quite a few non-native speakers on this forum. No worries.