How to clean your trackpad?

Cleaning your Apple products - Apple Support Do's

• Be sure to turn off your Mac, unplug the power cord from the wall or power strip, and remove the battery from portables or wireless keyboards and mice, before you start the cleaning process.
• Use a disinfectant wipe to wipe the area first, then use a damp, soft, lint-free cloth, and finally dry the area with another soft, lint-free cloth.

Don'ts

• Do not use disinfectant wipes containing bleach or disinfectant sprays in general.
• Do not use an extremely damp disinfectant wipe to clean the area. If you encounter a very damp wipe it may need to be squeezed to remove some of the excess liquid before use.
• Do not allow the liquid from the disinfectant wipe to sit or pool on the area being disinfected for a long amount of time.
• Do not use rough towels or cloths to dry the area.
• Do not use excess force when disinfecting the area around the keyboard; this could damage the keys.

My suggestion would be to take it to your local Apple Store and ask them to clean it.

There is every chance that if you attempt to do it yourself you will only make matter worst.