Sadly it's going to take some effort to fix this as you'll need to take the keyboard out to properly clean it or your other approach is just replace the uppercase.
As you didn't tell us which model we really can't give you more.
In the mean time turn off your system and don't charge it! Keep it cool as well until we can then guide you how to take your system a part.
Here's the IFIXIT guide you'll need to follow: MacBook Pro 13" Unibody Mid 2012 Upper Case Replacement. Once you get the uppercase off you can try to take the keyboard out to clean or you could just replace the fully assembly.
Let us know which direction you'll be going once you decide.