Actually, the 810 is quite well sealed. There is even a flap over the USB port. The only place for anything to get in is through the back where you put the battery in. Because it is a rechargable remote you should not have to open that very much.
Unfortunately something got in there at some point and is hard to get out. I'm not suggesting that anyone open their own remote because you can easily break the little clips that hold it together. Not to mention you would void your warranty.
I can tell you that you can work your fingernail into the seem next to the arrowpad aiming your fingernail toward the face of the remote a bit because the lip is attached to the bottom or back of the remote and fits up into the face. It snaps open pretty easily in that area, then you can work the other clips open little by little and it will come open. Also, don't use a screwdriver or anything as you WILL damage the case
