[iqman]

This items cannot be sold by default:

if(isEquipped())
return false;

if(player.isGM())
return true;

if((customFlags & FLAG_NO_TRADE) == FLAG_NO_TRADE)
return false;

if(isShadowItem())
return false;

if(isTemporalItem())
return false;

if(isAugmented() && !Config.ALT_ALLOW_DROP_AUGMENTED)
return false;

if(!ItemFunctions.checkIfCanDiscard(player, this))
return false;

return template.isTradeable();

is one of them fits you?