Here's an easy & effective solution.
I like to keep my MBP's / MBA's clean & looking new. To do so only requires a few minutes weekly.
Buy some denatured alcohol, it doesn't leave the slight traces of residue/additives found in rubbing alcohol.
Using a clean microfiber cloth I moisten one end of it and lay it on the trackpad for a few moments. It will wick up the skin oil into the cloth (no rubbing required) once you remove it, allow the alcohol to evaporate.
Your trackpad will look like new and stay cleaner for a bit longer as well.
Apply some alcohol to the middle of the cloth and use it to clean the keyboard. If done weekly it reduces the shiny area where one touches the keys and also leaves them nice & clean.
This is so easy, I'm always getting compliments on the new look of my Macs.