We have been forwarded this message by an artist:
I have recently come through (unscathed financially) the following scam which I suggest you tell as many people as possible. If you sell your work from websites or over the internet in any way, beware.
Someone who calls himself Broeer Zetman from Sweden asked (by email) for some prices of carvings from my website and I sent him a list with prices. He wrote back choosing about £3,000 worth of work and said he would send a cheque for £5,500 to cover the costs of packing and shipping to Sweden. The cheque would be paid from a British Bank by a customer of his. My offer to do the transaction by Paypal wasn't taken up. Eventually the cheque arrived and I banked it. It showed up in my internet bank statement as 'cleared'. I was suspicious so I didn't send my work off in a hurry. On later communication with the bank, I learned that they (the bank) can't guarantee ANY cheques to be cleared unless special arrangements are made on presentation. Then I learned, after further requests that the cheque was invalid (I presume counterfeit or stolen). I was lucky because I didn't get to the next stage of the scam which is something to do with writing a cheque yourself to the 'art buyer' to forward onto the shippers. When this happens, you lose your money and then you find later that the incoming payment in your bank doesn't exist after all.
Scammers often try to trick people using similar "cashback" schemes. Here is an article on the Metropolitan Police website which describes this kind of fraud in more detail.