On 2013-05-14, ARW wrote:

Tim Watts wrote:
On Tuesday 14 May 2013 18:51 Jane Frith wrote in uk.d-i-y:

I have a problem with my washing machine not working 100% correctly
on the rinse cycle with concentrated conditioner.
I have determined that the problem is the low flow of water through
the conditioner tray during the rinse cycle.
The low flow is caused by blockage of approx 2mm size holes (twenty
in number) in to the conditioner tray.
I have cleaned them out as well as I could -- and removed quite a
bit of black
"gunge" which was soluble when rubbed between fingers in water. It
appears to
be mould/bacterial growth of some sort. The only thing flowing
through the pipe/machine to that point is mains cold water.
....
The d-i-y questions: any ideas what the gunge will be and what could
I wash the pipes equipment tray with in order to dissolve/remove it?

Your gunge is probably growing in the machine - have you seen it
anywhere else that is fed by mains water?

As for the tray - take it out (most unclip) and wash it in host soapy
water with some bleach.

What's wrong with using the dishwasher to clean it:-)?

If I read the OP's post correctly, the gunge is in the "ceiling" of
the slot that the drawer fits in. I discovered (the deadly) black
mould in our previous washer-dryer & never quite managed to eradicate
it, so I'm making some effort to prevent it in the new one (leaving
the drawer out for a while in the morning if I'm not in the kitchen;
wiping the slot out with surface wipes; spraying alcohol in it &
brushing it).