I think I've dropped about every tool that I have in mud/under water. Tape measure doesn't even retract all the way after going for a few swims.... I feel like I need to go to confession or something.
I too am an electrician, with a lot of underground under my belt. Keep 3 in 1 oil on you pliers, work out all the grime. Stretch the tape out and douse it with WD40 and wipe it good with a rag, it'll go back to normal. When i do a lot of underground work i tune up my tools like this daily.