My scanner is over 5 years old and I never worried about it since it's glass and to scratch it would take a lot of pressure.
I think you are overly worried here.
I am soon to scan thousands of papers with stapled photographs on them. (The staples cannot be removed.) Because of this, I will have to flatbed each one.
Is there any kind of protection I could lay over the glass for these scans that won't change anything of the image scanned?
I read about a sheet protector, but the sizes were way too large. Could I lay another sheet of glass over the scanner glass or would that change the actual scanned image? Ending up with a scan of the paper and photo, but with a refection of the glass showing, or something like that?
We also have the three ring plastic pages that we could insert the pages/photos into, but to do that for each of them would add a lot more time to the scanning.
Any other ideas?

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