Excuse the suggestive title, I don't intend to offer you any NSFW material.
Now that we have that topic out of the way, I must inform you of my problem.

I just bought a new, Brass nut for my P bass copy, and after removing the old one (and breaking it in the process) I put the new item in.
After this, I have realized that the height of the nut is too low (despite measuring three times, and checking against the original) and the string touches the first fret.

What could I use to prop the nut up? and would using different things end up changing the sound?

I've been told to use cut up bits of old credit card, is this a wise idea?
Dunno, but where'd you get that brass P bass nut? I just bought one and now I'm paranoid
A guy off ebay, Don't get me wrong, the thing sounds absolutely amazing, it's just the first fret, and it's only the E string
If it's only the E string then a wedge shaped sliver of wood for a shim would be good, as you can sand it to the right shape and you won't be raising strings that don't need it. A Credit card will work if you want to raise all the strings by the same amount.
I could always cut the card like a "half- pyramid" sort of shape, that should do the same job as a wedge
Thanks for the help guys, I'll let you know how it goes.
It went excellently, I used a little bit of margarine tub lid, and made a small piece to elevate just the E string. Works beautifully, clears the first fret, and no troubles later on down the line!
Thanks for your help!