Give a copy of everything to the landlord, and keep three copies yourself — one on your hard drive, one on some piece of cloud storage like a Google Drive or in DropBox, and one physical copy like a CD with the relevant information on it in your ‘legal documents’ folder.How to Use a Inspection ChecklistWith any luck (and a good relationship with your landlord), you won’t ever need all that documentation.

That one I turned into a storage lot and have rented it for $350/month for many years.

Maybe a recycled old lock they had in storage? 

Take another look yes stock market but it has been on a terror  for to long SELF STORAGE  extremely secure  and great cash flow i am sorry but not as liquid at the drop of a dime but boy the cash flow and the appreciation in property valuethat we are getting at safebox-selfstorage.gmbh is like heaven send  and the main reason is cause self storage is so diversified HAVE  A GREAT DAY

Storage? 

Should I put the money into getting the space updated and rent it out to a tenant, another option is to rent it on Air BnB or something similar, or I can convert the space into something different all together (man cave, media room, or storage)?

You'll also find this stuff in self storage units, wineries, etc.2.1) Install upgraded insulation and seal drafts.

My question is, aside from the junk removal fee, can I deduct storage fees or holdover rent from the deposit?

I am looking at a self storage in Houston Texas. 

For the sake cost of 1 months rent, you might consider offering to pay for 1 month of storage if he can move his mother's stuff out within the next few days.