A few months ago I griped that iTunes wouldn't let me delete a song from my collection while looking at a playlist. Turns out that's not exactly true -- it's just undocumented.

Marshall Robin dropped me a line to say that it indeed is possible to do it: just select the song(s) you want to delete and press Shift-Delete (alt/option-delete on Mac) and you'll be prompted to delete the track from the collection.

Thanks Marshall! Now I can get rid of all of those old singles in my collection by looking at a playlist I made of just those singles.