Tom got another one from Freecycle and it has some filters inside.
Previous history
Update 2023: Old one was disposed of.
Update 24/02/2020: There's a chance that the motor is not misaligned but instead there's a filter missing and it erodes the graphite brushes due to high speed.
Tom got this second hand and gave it a cleanup but after a couple of tests the motor misaligned, brushes started eroding and the built-in thermal fuse blew. Feel free to fix it and/or reuse its parts.