The don't necessarily "cut" rust, but can lubricate light- to moderately rusted nuts and bolts enough to ease their removal. -some penetrating oils, notably WD-40, have water-dispersing qualities and are good for driving water out of electrical components.
How do you penetrate rust?
https://www.youtube.com/watch?v=xUEob2oAKVs
What is the best lubricant for rusted bolts?
If the bolt is stuck in place because of rust, you can use a bolt loosening spray such as WD-40 Penetrant Spray. This penetrating oil provides deep lubrication to loosen the nut or screw.Feb 4, 2021
Is WD-40 a good rust penetrant?
WD-40 Multi-Use Product protects metal from rust and corrosion, penetrates stuck parts, displaces moisture and lubricates almost anything.
Can I use WD-40 instead of PB Blaster?
A: PB Blaster is a penetrating oil intended for loosening rusted joints (threads, etc). WD-40 is a "Water Displacement" treatment intended to leave a persistent rust-inhibiting coating behind, and resist washing off exposed parts. Both are oils, both do almost the same thing, but each has it's own subtle differences.
A mixture of vegetable oil with 10 percent acetone, the active ingredient in nail polish remover and some paint thinners, works as well to free rusted bolts as WD 40. And it costs about one-tenth of the price.