Can anyone help me remove a stuck fuse holder from my tube amp?

Mike,
To be clear, the plastic cover won't come out, right?

Try some strong duct tape. Attach and pull. If that still isn't enough, super glue on the end of a dowel. Use a razor after to remove.

Best,
E

Yes, it just turns. The other fuse came out when I turned the slot 1/4 turn counter-clockwise.

Thanks! I'll give it a try!

Maybe try compressed air.

Replace the fuse holder!
https://www.amazon.com/dp/B005T6O72M/ref=sspa_dk_detail_4?psc=1&pd_rd_i=B005T6O72M&pf_rd_m=A...
You can’t use that holder even the fuse is out.

Had this occur several years ago.  Depending on the design of the fuse holder, it often is fastened to the chassis with a thin ring nut on the inside of your unit.  If/when these become loose, the entire fuse holder will then rotate disabling your ability to execute the typical 1/4 turn to extract the fuse.  This requires that you take the amp cover off to visibly see and access the fuse holder from the inside, and then tighten the ring nut.  If this is not the problem, the visual inspection from the inside mount should reveal why and what the problem is and then you can address it.  Unplug your unit first!!  If this fails, bring it to a shop.