you can use Plasti-dip, which i perfer. and you dip the servos and reciever in the plasti-dip. let it cure fully. than cut out the servo horn on the servos and the plugs for the Rx and you should be good to go. just remember not to go to far in the water as to cause it to get into the air filter element, that would be bad news. but it should be good for snow, mud and some nice puddles.
Plasti-dip can be found at like Home Depot or Lowes is where i got mine from. comes in spray or dip. i like the dip cuz it comes in a variety of colors to match your vehicle. i think its in the How-To section of the forum for more details.