I know that you've found some grease, but I'd audment mingusfingus' response regarding WD-40. Actually, I would not use it at all. WD-40 may seem to lubricate (because it is a petroleum chemical based cleaner), but it actually removes all the (existing) lubrication and also attracts dust. I'd use it to clean off any dirt or grease, then I'd wipe them down, finishing it off with the appropriate lubricant.
I would recommend some 3-in-1 oil - just use a very small amount, and it'll do you just fine.