My inlaws have a full basement under the house. My FIL has a work room with great tools and a desk set up, desktop computer etc (It is where he always hid from crazy wife/MIL). He has a Lathe in the basement to give an idea of the type of tools.
However, most of the basement is row after row of industrial metal shelving that stacks 4 high all the way to the 10 foot ceiling. It is packed with boxes of records and other stuff. My MIL has also filled another bedroom or two with boxes etc. She told my wife that she hid money in different books and files. What is it? Well my MIL's uncle Sol had an accounting business in the early 1900's so it is all his records, and ......
By "hiding money" she means she put a $5 bill or $10 bill in something every so often. My guess is at least $200 scattered about. All of which any one of you can pull from the industrial dumpster we are going to drop everything into when she is gone.