To "deshit" is to remove shit, garbage, trash, crap, or other excess baggage in the place you live, or in your life in general. To get rid of shit that you don't fucking need is to deshit. To elminate stuff that you damn well know that you don't need or use.
Alternate use, is to refer to emotional or psychological baggage. To remove or attempt to remove mental weights or mind-traps that are clogging up your brain with unnecessary shit.
I'm going to deshit my apartment. I'm giving away a bunch of clothes and furniture that I don't use or need. I am getting rid of shit -- I am deshitting!
My girlfriend is to damn needy; she's got a ton of emotional baggage. She needs to deshit her hangups, or I will fucking dump her ass.