I did a little write up on them in their section if you'd like an idea of their work.
Erm, just until it works really.
If it's quite bad (which it usually is as I'm lazy) I'll spray it, leave it to dwell and go around with the bottle and a microfibre to agitate/wipe away the more stubborn bits. Then pressure wash off.
Cheers mate you're a star.
Do you have any experience of Swissvax and Zymol products?