There's a product that's been around since the 1940's which continues to work, as long as it's wet.
The manufacturer also invented bonnet mopping and o/p cleaning.
I trialled the product some years ago and found it to be excellent, but it was a pain to have to keep importing from the States.
Robbie
It's called Argosheen and it really works........OOPS, forgot, other people read this board