Welp...
You have a bit of interesting delima, now don't you? I should first tell you that finding 2cb on the open market, espescially in the US the fucking rare. Also 2cb, though highly psychoactive, is a 'kinder' than LSD; occasions of 2cb induced drug freak outs are low.
Should you keep them?
From the perspective of simply having something that in the psychoactive community is a rare commodity, I would tell you to just hang on to them. Don't rush off and try it if your not ready!! 2cb, like MDMA is a very stable material and will hold up against time. Just store them somewhere cool and dark. 2cb should not be viewed as 'rave friendly'. Though it does posses enthogenic properties, the experience is more of an introverted variety.
I too have found myself in the same boat as you. About a month back I bought what I thought was ecstasy, tested, and found it to be 2cb. Shrugging, I simply popped them into an old pill bottle, put them in the med cabinet, and haven't given it a second thought since; this about 6 months ago.. still there. I will most likely save them for camping trip with friends as 2cb reports seem to favour outdoor experiences.
Can you mix it with MDMA?
From all detailed trip reports and from what I can derive from PIKAL, it would not be much of a physical issue to mix the two. Just understand that 2cb is very dose sensitive. Taking too much can send you to a bad place. The usual dosage methodology consists of a people taking their MDMA first, waiting until the peak subsides, then taking a small-moderate dosage of 2cb. From what is known, the enthogenic properties of ecstasy will still be pronounced and adding to 2cb's psycedelic push, the experience will be a visual rollercoaster ride coupled with the effects of a mild roll.
Hold on the nexus friend, you never know when it will turn up again.
[This message has been edited by underscore_omega (edited 13 May 2001).]