Silvered Constantius II Falling Horseman

Electrolysis can be the answer sometimes just be sure the coin is not over corroded first. Top sellers from london uk, balariks etc. all use Electrolysis to move hard dirt, it all is depending on liquid used and price of unit used. Cheap unit is cheap results. coin in post is common, grade is 1+ and value is less to 2 uk pounds.

You are a new member as such some of the functions are not available to you yet.

I don't care what anyone says, DO NOT USE ELECTROLYSIS. Sure try it out when you know what you are doing, it is a cheap and nasty fix which will strip any patina from the coin.

NOTHING compares to long soaks in distilled water (my favourite) or olive oil (I don't use it, others do, but it darkens the patina). Above all, patience is needed. Soak, brush, soak, brush/pick. You will get the hang of it and get to know when to brush and when to pick. It can take weeks or months, or just hours. Go slowly until you know what you are doing otherwise you will destroy a potentially good coin.

It is difficult to say from the photos. Be very careful when using acids. Ben is the chemistry buff.

You don't want to clean down to the metal. The coin should have a patina under the crud. You want to remove the crud, leaving as much of the patina intact as you can. I only use lemon on silver, and sparingly, washing off after just a couple of minutes.

I have no idea what those coins are.

Don't know what happened to your "Patina" thread but...
Well I can't tell from the photos whether they were that great in the first place. They are wildly off center and as I said before, I don't know what they were to begin with :)

In ancients, the last thing you want to see is a bright glossy coin, quite different to modern stuff. The patina is all important to ancient collectors.

If you have a look at the link below, you will see a coin posted by Dutchgulden - Diadumenian with the most glorious green patina. The coin as it is 10 out of 10. Take off the patina, back to the bronze, 2 out of 10.

https://goccf.com/t/164410&whichpage=2

I agree with Pish, electrolysis is not a good way to clean ancients, our any type of coin for that matter.