Surface mount electronics can be problematic when things get wet.

The issue is that the thin leads and legs from the surface mount components can form a channel or barrier to prevent the water from drying fully or for a very long time.

Water will remain hidden under the soldered components, only to later short out your device when you turn it on or it is in use.

Typically I use electronic component "bath" sprays, which use a highly aromatic liquid to help displace the water. Care must be taken with this stuff, because it evaporates so quickly that water can condense from the air due to the temperature drop.

In lieu of something like this, you can attempt to blow out all liquids with compressed air ( don't use a "can" of air as this cools too quickly exacerbating the problem! ). Once you have done the best you can, place the component in a bag with a lot of rice inside. Rice absorbs water helping to dry the electronics.... then WAIT, WAIT and WAIT... at least TWO weeks if not longer.

After this time, try your receiver outside the plane and range check it. Also while moving a test servo, tap the receiver to see if any moisture dislodges and that everything is sound.