Everybody loves a toilet thread, so he goes.
Our cassettes had go a lot of sediment on the top slide mechanism, tried various thing but it wouldn’t clean off.
I thought I would give this ago.
www.wilko.com
I put most of the box of powder in the cassette and then put a litre of hot water in.
Put the box upside down for a couple of days and then turning on its side for a day for on each side.
I then put the small amount of powder left on top of closed flap with more hot water to clean the flap.
Now got a nice clean cassette.
Our cassettes had go a lot of sediment on the top slide mechanism, tried various thing but it wouldn’t clean off.
I thought I would give this ago.

Descalers | wilko.com
Remove limescale to keep your appliances in tip-top condition with water softeners and descalers. Shop water softening tablets, gels and powders at Wilko.
Put the box upside down for a couple of days and then turning on its side for a day for on each side.
I then put the small amount of powder left on top of closed flap with more hot water to clean the flap.
Now got a nice clean cassette.