In the past week, some PLA+ I've been using for a couple of years has started misbehaving. Jammed extruder, clogged hot end, the works.

I've disassembled the whole printing head about 5 times. Done cold pulls. Swapped the filament for a fresh spool. Replaced desiccant. Lubricated stuff until there's less friction than in space. Nothing worked.

Until I printed with the printer door open to let some air in.

It's hot in Belgium. So hot it's starting to impact the properties of materials.