DOOR SEAL
This black on the door seal is mold and is what you get in a warm moist environment.It wont come off the only way is to replace the seal.
If you have this gunge on your door seal then you are either using too much powder or using liquid (depending on water type ).Use a biological powder whenever you can as it keeps your machine clean.
THIS IS HOW I FITTED IT
UNPLUG FROM MAINS.
Remove spring loaded wire from around door seal,place screwdriver under spring and prise out ( if spring is at bottom it could rust and break).Release door seal from front panel.
Remove the door seal from around the front panel.
Reach inside and press the seal nearest the drum and the seal , and spring should come away.
Pull the old seal and the spring away.This arrow is used to line up the new seal (it is at the very top).
This lug on the seal must line up with the arrow at the top of the drum.
This hole should be at the bottom of the seal.
Now fold the outside of the seal back and offer it to the drum.Do this all the way around the seal it`s a bit fiddley but it fits eventualy.
Push the seal out of the way.
Get the spring off the old seal.
Line the spring up with the grove around the seal ( from the top )and stretch it to fit (not too much or the spring will stretch permanently).Three hands are great for this job.
Fold back the seal and push onto the front panel as shown. .
Replace the front seal spring to secure the seal.