Just scene tax Robin, your common or garden stuff is fine, but anything with an ounce of rarity seems to double in price as soon as it lands on a VAG forum.
Usual trick is to get a few key people to talk something up, go to a few shows and be seen/scene, then sell them for a rediculous amount of money a few weeks later in the hype. Usually to some kid who gets up to their eyeballs in debt trying and play with the big boys and so it goes on and on...
I'd prefer to simply get back what they owe me and sell them to someone who is going to use them for what they were intended.