Break-free. Won't get gummy like wd-40 does, and lubricates much better in my experience. Both break-free and wd-40 are solvents, kinda like kerosene, but break-free also has a teflon based lube. Used to be the army used it for weapons storage/cleaning/lube, but like any oil it attracts dust, so not good in the fine sand. Either may remove paint. You can get break-free pretty much anywhere they sell gun cleaning supplies. You just need a tiny bit. If you just want to clean you can use spray carb cleaner, but that will pretty much take off any paint.