One 3D printer owner has devised a simple method of solving the “wet filament” problem.
Wet filament is a big problem, particularly PLA filament. The problem is that PLA plastic tends to absorb water when exposed to the air. These tiny bits of humidity travel with the filament into the hot extruder where they boil and bubble in the hot end, causing print quality issues. In the worst cases, the filament itself swells up to higher diameters, potentially causing extruder jams or inconsistent output.
Several solutions are commonly used. The easiest solution is to simply leave the PLA spool in its sealed shipping bag until you need to print. Then print it as fast as you can, before humidity can seep in. Another solution is to bake your filament spools in a hot oven for a few hours to ensure the humidity evaporates. However, that takes time and could mess up your plastic if you’re not careful with the temperature.
A unique solution we saw from Reddit user snarfy (image above) in which an inexpensive plastic tub is partly filled with crystal kitty litter. A spool and mount is placed in the tub, with a small hole for filament to travel through towards the 3D printer. The kitty litter serves as a desiccant to absorb humidity within the tub - and draw it out of the filament, too.
If you’re using this approach, we recommend a clear tub so that you can see how full the current spool might be. Also you may consider a much larger tub where you can not only store the active spool, but also any other not-in-use spools. Finally, this would also be an excellent place to recover your smartphone after you put it through the washing machine.