MacBook Air Water Damage

Hello All,

My MacBook Air 13" from 2013 has been sitting dormant for a year and a half, due to water damage. It does not turn on, however, it works with the charger. I have opened it up. I noticed on the logic board and on the battery that there are some water stains. There is also a break in a piece of plastic, however, I don't know if this plastic effects the computers performance. As well as this, there is some sticky, brown substance on one of the cords in the top middle right. Are there any obvious issues with it? Also, what should I do to fix it myself? Or does it need to be taken to an expert? Please note that the red marks are photoshopped on, used to mark spots with potential errors.

Thanks,

Lchogiez