How do I fix a key that presses itself randomly?

MacBook 13" A1181 2007

I have spilled milk on my macbook a few months ago and have cleaned it and everything is working fine except for some keys. One is the "<" key that randomly starts pressing itself or sometimes when I click it and release it will keep pressing and won't stop until I press it again or press any other key.

I was thinking of buying a new plunger for that key since I don't have one (I removed it because it was torn. But now I am not sure about doing that since the key is damaged.

Here's how it looks right now:

One other problem I have is I when I press Shift + W nothing happens, only works if I turn on Caps Lock and press W, it's really weird.

I was wondering what I should do to fix this.

Thanks