Could you fellows/gals tell me what this thing does its on my 2000 5.9 (Covered in oil)

The thing has to be serviced without a trip to the stealer. What do I do clean up this mess!

Thanks

 

oil blowby res you can remove it and clean it out were rubber gloves. when you get diesel motor oil on your hands it's tough to get them clean . It's a plastic bottle with a screw cap. put cardboard on the floor befor you remove it. Helps with clean up