Bankrupt the BNP

From Bristol Antifa:

Bankrupt the BNP!
Well, maybe not quite bankrupt, but folks in the UK can help make this bunch of fascists considerably poorer.
They've just got themselves a freepost address:
British Heritage FREEPOST
Nice and easy to remember eh? Every 'letter' to this address costs them 42p, and can simply be an empty envelope with the address on it. It's cheap to buy a bunch of these (you can get 50 self-seal ones for 75p from Wilkos) and run them through your printer while you're off doing far more interesting things. A friend has so far sent 1250 envelopes, costing the fash over 500 quid. That's less than £20 of my mate's hard-earned cash very well spent!
Please feel free to join in.
42p may not sound like much, but it would pay for dozens of BNP leaflets. Multiply that by potentially tens of thousands of empty envelopes sent their way and the impact on their activities becomes much more obvious. And when an envelope costs little more than a penny, it really does make sound economic sense!

We're advised that it's not worth sending heavy objects as they'll be filtered out at the sorting office, and we don't want to make our posties' jobs even harder than they already are.

Current good ideas are:
Christmas catalogues with your name and address torn off
Leaflets
Takeaway menus
Envelopes of glitter (it's hellish to get off your clothes, and the mental image of perpetually sparkly fascists is too good to miss)
Postcards or letters with anti-racist and anti-fascist messages
Chopped up cardboard boxes
Anything at all else you can think of. Within reason.