I recently came across my late grandfather's old pocket knife and noticed rust and other scratches along the bolster and blade of the knife. I would like to make it look as new as possible. Any ideas on how I can spiff the knife up?
It really only looks like the brass is having a little bit of oxidizing. Pick up some Brasso and carefully with a cloth try to buff the bolsters out a bit. Overall, it appears to be in good shape otherwise. Lightly oil the back spring and pivot, and sharpen the blade.
When I clean up knives like that, I typically use a stiff sponge/pad and WD-40. That usually does the trick. Best of luck.
Your knife is not particularly old, but it certainly looks beautiful.
For polishing it, I suggest using Brasso, as Liam said. Dip some on, then buff it off. It'll give it a nice shine. It works on steel just as well as brass, so don't be afraid to use it on the blade.
If it's stiff in opening and closing, a squitz of sewing-machine oil, or WD-40, if you don't have machine-oil, will lubricate it. If that still doesn't work, a dunk in an ultrasonic bath will almost certainly help. You can buy these machines from electronics and homewares stores. There's big ones used by professional restorers, but the household ones can be used for stuff like jewellery and whatever. And that'll clean most things. Including the dust and crud inside the handle of your knife. Just make sure you dry it promptly after the sonic bath, so you don't damage the wood on the handle. Any issues produced by the bath on the metal can be removed using Brasso.