Any kind of storage would be a natural, and easy. Or how about a combination coffee shop and tool supply?

If you own the building and it is a large space and you are in a desired location; I would just alter it and turn it into office space and or warehouse space and rent it out. I don’t know where you are located but where I am; you can rent out warehouse/office space by sq.ft.

Your buisness will be the ‘landlord’. In this situation you are not wasting or investing/risking any money into a business that may ‘fail’; rent is a solid investment and you can turn that extra cash into something else!

In terms of document storage; everything is going online now on servers etc; only old school businesses would need document storage; shredding business sounds more plausible, but the sunk cost for that and the advertsining costs, operation costs may not be worth it…

If you can rent, why not. You can go play golf, sit at home and read..

(other suggestion would be to start a non-profit; something you truly believe in; raise money, fund-raise; leave your imprint on our planet). Good Luck.

You may have to check the zoning for the warehouse. Some business may be prohibited. Extreme example: if you wanted to open a strip joint. These require separate types of zoning. I would check. It would be a shame to set up a business and then find out it violated the zoning requirements.