Originally shared by Harry Rabin
Baked a moisture-damaged roll of Bridge at 90C for 90 mins, and found this when I was done. Oh well! At least the filament is dry!
If you have an airtight box, a fresh batch of 4A molecular sieve desiccant (about $30 from ebay) will get the relative humidity of a relatively large volume down to <5% RH, which will dry out almost anything, albeit very slowly given there’s no heat.
You can the re-use the desiccant by baking the crap out of it
Yes, indeed, an investment that can last a lifetime. To be honest, though, I’ve had trouble restoring molecular sieve back to it’s original effectiveness. Brand new sieves can take RH down to 2%. I haven’t yet been able to regenerate sieves to that level in my oven, they seem to max out at 4% RH. I saw some guy use a microwave in a lab video on YouTube, I need to try that.
@James_Kao It might be worth trying blown hot air (that’s how the industrial driers I saw worked)
Been there, done that. 
Mine was worse, the roll was standing on its circumference, the shelf bars melted the rim and pressed against the filament. New definition of Fused Filament…
I have a spool that looks the exact same…