I noticed that around that switch (on the plate), there's this layer of dried yellow grease-like thing, and when I wipe it with alcohol, it melts and wiped off. It's only around that switch, which leads me to believe that when the keyboard was put together, someone accidentally dropped that yellow grease right on the switch, which then seeped inside. It probably dried and only was affecting the switch a little bit since it's just along one side of the switch's inner well. But once I put alcohol in and swished it around, it melted the grease and now it's all over the switch and completely gunked up the inside.
So I'm guessing if I keep diluting the inside of the switch with the alcohol and then try to blow out the mixture with compressed air, I'll eventually thin the grease enough to the point that it won't gunk up the switch anymore.
If that still doesn't work, then I'll have to send it back.