I use a cable lube tool I have had around for about 9 years, so have no idea who manufactured, but they are al built about the same. Once installed, I use carb clearner and spray through the cable to clean it out. Using an air hose, I spray into the lube hole made for the little red hose from the can to help the carb cleaner flash. I then spray with WD40 until it is coming out the bottom. Finally, I use only stock cables, as I have found them to outlast after market cables I have tried, and I usually replace my cables about every 12-18 months.
Rick