Gas pedal

What are you trying to remove? Are you talking about rust on the metal part or something on the rubber pad? Chrysler has two real good cleaners called "Total Clean" and "Super Clean" for grease stains, bug juice, road tar and stuff like that. For rust just use what you'd use on any other metal items. Sandpaper and steel wool are common.

My pedal is sticking when i press down on it sometimes do i am trying to figure out what the problem is

Ohhhh. I was thinking of something completely different. It's very unlikely the pedal itself will stick, and the same with the cable. First look at the floor mat to see if the pedal is catching on it. It is also possible to have worn bushings in the throttle body, and the shaft can catch on them. That often doesn't show up when rotating it by hand under the hood because you're tugging on it from a different direction. Instead, push slowly on the pedal until it sticks, then hold it there while a helper pulls on the cable under the hood. That will show if it's the throttle blade that is sticking or it's something else.

Well i had an error code saying that the throttle cable is not free. I took it to a mechanic and he said it was something underage pedal.

There's no such thing as a diagnostic fault code for a sticking pedal. That is not something that is monitored by the Engine Computer. Do you know the exact code number(s) you had?