My DIY filament dryer using a Folgertech Kossel & heatbed set to 40c. This plastic roll seems to have quite a bit of moisture in it. Since I did not have a filament dryer & my oven will only go down to 150degs F, I came up with this idea. I am using klipper firmware & set my [idle_timeout] for the temperatures to 3600 seconds, so it will only heat for an hour at a time in case I forget about it. I put a weather sensor on top of the filament to see what the acutual temp was on top. It has taken 10 minutes for that sensor to get to 27c. Probably need several hours, but will see what 1 hour does. I was going to use a large metal cooking pot, but this big glass bowl fit on nicely & I can also see the filament this way.