3DS ABXY Buttons Repair, HELP!

[ShayBox]

I just found a 3DS in a car, filled with syrup. for pancakes... idk, i cleaned it and it all works except the L/R Shoulders, im going to buy the replacements for those, but also the AB buttons don't work, x and y does but its cause under the plastic cover, where the metal bends and makes contact with the board, theres syrup, but idk how to take the plastic off without breaking it, i can buy replacements, but also how do i get it off???

 

[ShayBox]

P.S. its this, they have syrup under them http://www.aliexpress.com/store/product/5set-Cross-Keys-ABXY-Key-Button-membrane-Button-stickers-Repair-Part-For-Nintendo-3DS-3DSLL-3DSXL/1354140_32413384277.html