Describe the solution you'd like
If it is possible, some integration with the Scrap junk seller addon would be needed
https://github.com/Jaliborc/Scrap
https://www.curseforge.com/wow/addons/scrap

reason: Need a button in the "Selling" tab to mark the current item being considered for posting in AH as scrap/junk, so that the Scrap (junk seller) addon can recognize it as something to be sold at the next vendor visit.

Describe alternatives you've considered
after visiting the AH and deciding not to list some items, except just manually reviewing leftover items in bags... there is no real alternative that i could find.
I currenty have so many junk items (green/blue/purple quality) in bags that i literally gave up even manually reviewing them.

Not going to add an integration with Scrap. Possible alternative is searching for BoE&gear items in your bags and vendoring those. https://www.curseforge.com/wow/addons/baganator has a search box which will support that query and a one-click button to vendor everything matching the query.