Is your feature request related to a problem? Please describe.
I want to be able to mass scrap gear from old raids, but if i enable Sell Low-level gear, it can sometimes vendor my offspec trinkets and just current expansion gear in general.

Describe the solution you'd like
Adjustable Item level threshold or difference from you current max non-equipped item level

I would love this too, I've accidentally sold a few offspec pieces while clearing my bags in the middle of an old raid. After buying them back and manually setting them as useful, it looks like Scrap is misidentifying the item level (e.g. I have a 455 Jes' Howler, but when Scrap prints the "Set as useful" log message, it links to the 300 version).

An alternative to the slider would be a simpler "don't vendor anything from the current expansion" checkbox.