I was contacted 2 days ago by a thief. This technique is quite old (at least 3 years) but always worth mentioning.

Your bank will credit the amount in a few days but. . . the certified check is a stolen one that will take 3 to 4 week to be rejected by your bank. Enough time for robber to get the item and some money from you (they will pick up the item and ask for the shipping fees back in cash :-)). In the end you loose, your item, some cash, and can get in trouble with your bank if you ever did use the credited money.

Here is why they did sent to me

Dear Sir/Madam,
I am interested in purchasing this Bike it suits my requirements perfectly,I have two garages one in England and the other in the Netherlands i shuffle most of my time between the two.
THESE ARE MY TERMS OF TRANSACTION:
1) DO KINDLY GET IN TOUCH WITH THE LEAST PRICE.
2) I WILL BE PAYING WITH A CERTIFIED EURO BANK CHECK WHICH I WILL ALLOW TO CLEAR BEFORE THE PICKUP/SHIPMENT OF THE BIKE.
3) I WILL INCLUDE FEES FOR SHIPMENT IN PAYMENT, THIS MY SHIPPING AGENCY WILL USE FOR PICK-UP.
The excess funds will go towards covering costs for shipping,shippers fees,insurance,tax and any other expenses that might be incurred getting it down to the new owner.
I will want you to get in touch with the following details if my terms are okay:
FULL NAME.............................
ADDRESS.......................
TELEPHONE NUMBERS....................(Mobile and Land)
As soon as i have your details i can have payment effected immediately all things being equal we should have this wrapped up by the end of this week.
Please note that you'll have to send on the balance on the funds that you'll get to my shipper so he can come attend to the pick up as soon as you make the Bike ready.
I believe that most transaction are based on trust.
So I will look forward to a successful transaction with you.
Best Regards
Graham Colemanson