Any Ideas?

What is this gooey material? I changed my oil today and it was on the inside of the oil cap, and some in the oil line.

 

Too many short trips. You're not letting your vehicle reach the operating temperature for any length of time.

 

Gotcha. Makes sense, as my work is a real short drive. Any suggestions for cleaning it? Or will taking my truck for longer rides every now and then do the trick?

 

Water mixed with oil, like dtaco said, condensation is mixing and making that nice goo...Drive longer and let the truck come up to operational temps. How to clean, Carb cleaner!

 

Moisture gathers under cap because that's the high point in the crankcase. Just wipe it out of there.. and get the truck out on the highway more

 

Either a blown head gasket or condensation.

Depending on factors it can take 5mi or more to reach operating oil temp.

So if daily work trip is 2 mi then that would leave condensation.

catch can supposedly helps.