By now, i have plenty of @gdrags containers in use (original idea seemingly by “Malolo”).
I only used the original containers to put them in dryboxes.  
My main problem was fitting them into Prusament spools as i wanted, and especially keeping those spools from serving filament-spaghetti when drying them at high temperatures due to rapid unscheduled disassembly.

After running out of long bolts to clamp my Prusament spools together for drying, i thought: why not fix both problems!?

Now the containers fit nicely inside the spools AND they don't fall apart anymore!

I printed in ASA and PCCF for high temperature use while under mechanic load, but otherwise PLA or PETG will be just fine.
0.3mm layer height works well, even with the threads.

Due to the thread and conical ends, the possible spool widths have some wiggle room, but you don't want that container to open itself, so don't overdo it…