I have got some Ottoman coins too but they are so darkened. I tried carbonate but it didn't work.How can i clean them without distrupting?
In case no one has said it yet--don't try and clean anything just yet. So many of the processes are quite harmful to coins and can destroy a lot of the value. That said, 'cleaning' around coin circles has a negative connotation as something too harsh/abrasive/metal stripping. You can learn safe, preserving ways to manage your coins--and figure which ones have value to make this important.
For those coins, there's really not much help. They're just too corroded to do much. Now I don't know anything about those specific coins, I have no idea what they even are - but that doesn't matter. Given the color, I'm assuming they're copper, and if so there is a product specially made for copper, it's called Verdi-Care. You can order and buy it online. But even it isn't going to do much for those coins because they are just too far gone.
The best advice is just don't do it. They are what they are. Cleaning is almost ALWAYS detrimental to the collectibility and value of any coin.
I made a product specifically for copper alloy coins since I am a chemist but like the Moderator said here 99.9% of all products will hurt copper. I do sell or give to people close to me say in the C4 world and I had no complaints other than the product has a limit. My product on copper will not change mint red, cartwheel effect, safe on copper proofs and their finish but when you remove 100 year old toning there is an obvious visual change. Removing soil also takes some skill as not to create hairlines so I warn on MS copper coins. Its complex just like the coin chemistry of a good copper cleaner. The other factor is the "degree" of copper oxidation so if its superficial it will work - if its severe and has gone into the coin's surface its probably best to leave or just remove the superficial film. 99.9% of all collectors believe you can not clean copper effectively. Who am I to convince them otherwise ... LOL. I may bring some to Baltimore this November 2017 when promoting my second book "Forgotten Coins". John Lorenzo United States
they look good as is to clean would take off patina but to clean with build up of dirt distilled water & toothbrush or can soak in regular olive oil good luck remember you can never go back once you clean but can always go back and clean DAN
Just for your information, that coin at the bottom right is not really a "coin" at all. It is a Galata bridge token. Based on your info, you may know about that bridge. I found one of these in the late 70s in a "5 cent a piece" bin and it took over thirty years to identify it! https://en.numista.com/catalogue/pieces11075.html
