Plastic piece near front frame jack points

Does anybody know what the point of these plastic pieces are on the frame near the front jack points?
I just got some ESCO jack stands and these are in the way. Are these pieces necessary? Can they be removed?

 

They are supposed to be one way drain valves for the boxed frame. I've crushed one of mine already. Truck still rolls...

That cross brace you also see in your photo? I removed it so I could install my MillerCat shield. Guess what came out of the bolt holes?

Water.

But I Fluid Filmed the hell out of the inside of the boxed frame, the water was clear... not rusty.

 

Yep, one way drains. We call them the oil change indicators. Most of them are crushed from the lift pads when doing oil changes.