I know that the issue of bogus 'charity' collections, where companies put flyers through your door asking you to leave clothes and other items outside your door, apparently to be passed on to the needy, has been mentioned before on this forum, but I was never really sure about whether there was any evidence that they really are bogus or not.

However, the Charities Commission is compaigning to let people know about this issue:

http://news.bbc.co.uk/1/hi/business/7124533.stm

Better to give any donations to a proper charity.