You can buy Chore boy copper mesh on ebay (that's how I got it) :

[URL unfurl="true"]http://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p5197.m570.l1313&_nkw=chore+boy+copper&_sacat=See-All-Categories[/URL]

It's definitely much better than stainless steel mesh, it's much easier to shape into a disc and I haven't had any bleed-through since I use it.

P.S : once again, thank you gibran2 for the advice...