You can soak them in white vinegar. About half an hour if it's light rust; overnight if it's a bit heavier. You should be able to just wipe them clean. If you need something a bit abrasive, Bar Keepers Friend is pretty good for this as well. (I use vinegar on my cutlery and also jewellery tools when needed. It works really well.)

Edit: Wash and dry them as normal, afterwards. You don't want to eat the rust residue.