Not the best foam I've seen, unless there was a lot more when it first went on. Not sure I'd wet it first though, surely just foam it and let it work it's magic?
My mate has one on his Subaru and during oil changes you can quite often see a very small amount of metal shavings on his. Looks sort of like iron filings.
Edit: Meant to say nothing to worry about though. His engine was rebuilt awhile ago and he's had it checked over a few times and it's just normal apparently to get a small amount like he does. That's why the magnetic sump plug is a good idea.
Cool, probably invest in a Tarmac one if they're the best?
So I guess the next question is has anyone had particles on their nut? Or is it just an earlier warning system and if you do find some on their its time to trade in? I think you're a right, no brainer for the cost, just wanted to discuss.