Delete a Won Quote

How can you delete a WON Quote that was converted to a contract. I tried to delete all associated charges and contract but I can not delete the quote that was WON and converted? Any suggestion?

Quotes that were won and converted into Contract/Charges/Ticket cannot be deleted or else the data integrity would have been broken. This works like this by design.

You may try to 'mark' such Quotes as 'not-relevant' by editing quote name and notes under Properties tab in the quote.