Although it rarely helps to lubricate the cables, if you want to try, take a 1 foot length of 1/2 in clear hose, trim a rubber tire valve to fit one end of the hose and clamp it well. Fill the hose with light gear oil then slide the open end of the hose over the cable end and clamp it tight. Next use a bicycle pump and pressurize the hose to about 15 psi and leave it. In about 30 min you will start to see oil drip from the other end and your done. Release the pressure and hook the cable back up. (If you want to get fancy you can split the hose and add a guage as I did.)
The system works great and I have done all mine this way with some improvement but truth is if they are starting to bind, they need replacing. Keep in mind when they break, it is when you are maneuvering the boat not out cruising in open water. I shudder to think of one breaking while docking in close quarters and a strong wind.