I had to completely remove the dual-drain plumbing which was coated in a whiffy slime, and completely brush and soak it before replacing.
My theory is that because we've started using the dishwasher a lot more (why else have the bloody thing) we are using the sink much less. Just running a bit of water to get the wooden things clean.
As a result the slime builds up and is never subject to a regular full- sink empty cycle which helps clean it.
Putting bleach down the sink doesn't really work, since it just trickles out, leaving the upper surfaces dirty.
One solution is to somehow seal the outlet, and fill the circuit up with bleach (maybe overnight) to completely touch all surfaces.
Another is to find a way to foam bleach into the pipes so it touches the top.
Is there a diy mix of stuff to do this, or is it better to resort to a specific product.
NB - drains are completely free flowing - not blocked at all, so it's not needed to dissolve a blockage. Just clean the top of the pipe.