Skarsten scraper blades

Depends on what you are using it for. For aggressive scraping to remove dried glue etc, then the carbide scrapers are pretty good. e.g:

Thank you for your help. I am trying to remove old and cracked varnish from external window and door frames. I will try both of those.

I did wonder about trying to use aluminium oxide triangular bits for a multitool, but they may get clogged up to quickly.

Also, bits of broken glass. Use gloves, obv.

Hot air gun? Mind, that can go badly wrong, but some paints come off easily in thick layers...

Thomas Prufer

If using a card scraper, you will need a burnisher for resharpening it... (plenty of videos on youtube for sharpening card scrapers)

Chances are the varnish will flake off fairly easily without clogging if you are lucky.

A chemical stripper may be another option.

(using heat risks cracking the glass)

I tried looking for Skarsten blades a decade ago, and they all seemed to be gone.

Googling "Skarsten blades" finds lots of hits, just beware that there are a lot of different ones. Skarsten made a big rang of scrapers over the years. I still have a few (an uncle of mine was company secretary for them for many years).