Okay, so you've probably got soda within the system. I'm hoping the system wasn't on when the spill happened. Anyways, what you're gonna want to do is disassemble it again and give the PCB (printed circuit board) and other electronics a bath in isopropyl rubbing alcohol (probably around 90% or so) either with cotton balls, q-tips or even submerging the PCBs in a shallow bowl then cleaning them off with a soft bristle tooth brush. While you're in there, make sure your sleep slider is properly seated†and reassemble after it's dried off.
That should get your system turning back on. If you don't see anything after that, I'd suggest one more isopropyl bath and we can trouble shoot from there.
†- I just fixed a 2DS that wasn't turning on by fixing the sleep/volume sliders. Whoever owned the system before me (eBay junk) must have dropped it on the sleep corner and popped it out of the slider. After reassembling, it turned back on. Yes, the plastic also has some soda stains on it as well.