My Mum used to work in A&E, and had to book a gentleman in who had suffered at the hands of his friends whilst passed out.
They had dropped his nuts individually into a Marmite jar, which of course worked fine. However, there was no way he could remove them together due to their combined width and the constraint of the jar neck.
I'm not sure how this is supposed to help admittedly, but I'd just go and buy some new Marmite given it's small cost. I would however recommend not placing your testicles in the empty jar, as above.