I stupidly cleaned my LS6 cam and left it un oiled for 2 weeks.
It developed slightest of surface rust ona few lobes and cam journal.

You can just feel the odd bit of surface rust.

Is there anything I can use to clean it up or should I just junk the cam?

 

I think would see how much comes off with 1500 grit paper. The lifters are rollers so... I'm no expert though. Here's a TTT.

 

Try some penatrating oil and a rag.

 

Steel Wool @ penetrating oil will make it look new again.

 

I used steel wool and penetrating on on my cam and it was good as new.

 

Soak it in WD-40 or other penetrating lubricant and let it sit for a while, then wipe it with a rag.