now hear me out, yeah this could be an exploit if its true... but if you can buy it for a copper... and you sell it to them for say average of 40p... wouldnt it be wise to sell rebuy and repeat? i mean hey how much cash can you get selling the same item over and over again till the npc gets smart? :P just a thought
I don't know where you got the idea this can be bought for a copper. (Maybe it could once, but if so it's been fixed.) I sold some to an NPC for 34.286pp each at max charisma, and the NPC wants to charge me 75.599pp if I want them back.
I just checked the vendor price on Seeping Murkglider Fluid and the vendor offered 100 plat for it, so the test about if it is worth a copper, not reliable, just so you know