Etsy Reticence

My attention was drawn a while ago to the sales portal Etsy, where there are a lot of craft items - but also over-priced (I would say) dugup antiquities and fake "antiquities". There are also some dealers who show items with nice patinas that they class as "Museum-quality Replicas". Some of them are nice and have a good vibe... others, umm... hm. This applies particularly to their attents at Greek or Roman figurines, and large-breasted fertility figures of any culture. These are difficult to imitate it seems. I was struck by one seller with a lot of items that had an intriguing patina that I'\ve seen before and decided to chance it:

10 hours ago13:46 EDT
Message:Hi, I am a British archaeologist and have been studying the antiquities offered by a certain UK antiquities dealer recently. Among them are a whole group of fake items that are supposed to be from the Middle East/Iran area that I realise have a patina very much like this one. May I politely ask what chemicals are used to produce this attractive effect, or is that a trade secret? (there is very little literature with real information on patination methods of the modern producers of antiquities that are not as-described). Thanks, sorry to bother you.
Paul Barford (Warsaw, Poland)

Roman Bronze Brooch Fibula Museum Quality Replica, Historical Copy, Reproduction PLN177.13 Add to basket
6 hours ago17:56 EDT

Museum Quality Reproductions
Message:Hi Paul,
Thank you for your interest, but I am afraid that I am not able to share it. Sorry about that.
Thank you!

So that's coming out of my basket. I was hoping I could get a chemical analysis and SEM of an out-of-a-bottle patina made by a known method. I already have some examples of the UK fakes (donated by a disgruntled buyer who asked my opinion) and it'd be great to do a comparison. It is also interesting to speculate if the reticence to share is due to the seller having their own recepie (or favourite one from fakers' lore), or due to the seller not actually being the producer and does not know. To my eye, these are not, for several reasons I'll not go into, imported fakes of Bulgarian origin.