Are those big enough for mimeos to grab?

Careful. If truly determined people are hunting, microscopic particles trapped in the glue could be traced back to you. The specific magazines might also be identified from the letters and traced back to you.

All that I'm aware of. Or to put it another way: every typewriter you're likely to encounter out in the wild.

It's a common trope for old whodunit mysteries, so I bet someone solved this particular problem but I'll also bet that they're not common machines.

As a person who submitted multiple school papers on a '95 typewriter I can say this: the "newer"style presented a similar issue. Pressing a key was similar to pressing a key on a computer keyboard, as opposed to traditional typewriters where the key press is physically pressing a stamp into ink paper (the ribbon).

I'm not sure how the 1995 one worked, but there were no physical stamps, and it required power. It still left a visible impression on the ribbon though.

This one was fancy and had multiple ribbons in a cartridge. The bottom ribbon was ink, but there was also a highlighter ribbon and an eraser ribbon. For the time, this was very high end. Almost like having a real computer!

The ribbon is just 2 wheels on gears, that work the spool of ink ribbon from one wheel to the other. I've taken them apart a few times, and yeah you can just read what was typed. If you have a fancy one that does erasing, both ribbons move the same, so retyping will end up with a ribbon that has jumbled letters. On older typewriters you can still manually move back on the line you are working on. Depending on the machine, and it's mechanics, it might have a "backspace" button that might roll back the ribbon as well.

It's not going to remove letters, but you can go over the same space on the paper multiple times. (As example: you accidentally hit "a" instead of "e". You hit backspace to readjust to where the" a" is. You then press "e". Repeat that 5 or 6 times, and the "e" should be visible on top the original "a".)

If I'm not mistaken, there used to be typewriter tape available, might still be available. Used for instances that the ribbon gets tangled and you have to tape it back together. If that's the case, just rig the receiving wheel so that you can remove used ribbon. Burn the ribbon and done.

pro-protip: use tails.

Ceramic tile, rice paper, food coloring, fountain pen.