Cleaning a dirty daguerrotype

My brother has a big birthday coming up, and I want to give him a daguerrotype I have of our ancestor who had the same first and last name. It dates back to the 1850’s, according to a note on the back. The problem is that it–and the man’s face in particular–has grey “dirt” on it, sort of like light shading done with a pencil, though it’s highly doubtful that’s what it is.

I know better than to try to clean this myself. However, all the photo restoration places I’ve found online (hither or yon) do digital restorations. I don’t want a photo-shopped copy; I want a clean original.

Is such a thing possible? How would I find a reputable place?

Thanks for all suggestions!

Isn’t it a thing on Antiques Roadshow where they say, “Well, this would have been worth a lot of money…till you had it cleaned”? Patina=value?

DO NOT TOUCH the image side of a real daguerreotype.
The image is on the backside of the glass, and is very fragile. The front side can be cleaned.
There are other processes that are often confused with daguerreotype - is the image a mirror if you look at it at certain angles?

This detailed description strongly recommends this site for high-quality daguerreotype conservation materials. They would probably be able to help you find a restorer.

Well, this is embarrassing. I was told this was a daguerrotype and assumed a daguerrotype could somehow be printed on the very thick paper commonly found on photographs of the 19th century. So, no, not a daguerrotype. Nor is it a tintype. It’s definitely from no later than the 1850s: the style of dress indicates it could be 1840s. Think Eustace Tilley, the New Yorker mascot.

My apologies. I still need to know how to get it professionally cleaned, but I’m sorry for troubling everyone with my error.

Many thanks for the replies.