I'm afraid that they've now gone into minus value,so you'd be better of just giving them all to me for free :)

(naah,joking)

I remember someone posting a link on here a while back,some COSHH records going for a ton each!! Other than that,have a little look on some of the second hand music sites and see what they're charging,give you a rough idea of how much you're sitting on. :)