I'd just use localbitcoins to convert as I have in the past. It's never taken longer than an hour to covert BTC to fiat. I have a Paypal debit card, so once cash arrives there I can access it instantly.  For paypack it would be the same in reverse. Other than speculation or possibly converting one crypto to another I have no idea why anyone would bother with an exchange.  Not too sure what I could use for collateral, assuming I shipped something unless I sent it express I'd have the loan paid back before it arrived.  A shoe on the head pic is no good anymore? j/k

edit: would a pic of the decommissioned equipment I'm selling help any?