Guys...It's been a while since I checked my own thread. First, thanks for the ideas. I'm still mulling over my options and sorting through what to do with things.
For now, though, I got a tarp from Harbor Freight. I put down a wooden "shelf" I built for the shed several years ago along the wall of the house on the side yard, and stacked the chairs up along that, and covered them with the tarp. I also moved the engines and transmissions and other big parts back outside for now and covered them with an old tarp. I got rid of some junk plastic tubs and crud on the side yard that I was intending to get rid of for a while. I haven't had a pickup since 2004 (though I plan to remedy that soon), so that has slowed many of my project ideas down because I need the truck to run stuff to the dump, Goodwill, etc. in order to make room for the stuff I want to keep.
One of my ongoing "to dos" for the house was to add more blow in insulation in the attic. In particular I wanted to insulate over the garage to keep it cooler. A couple weekends ago I spent an entire weekend in the attic blowing in 72 bags of insulation, which hopefully will keep the whole house cooler and drive down my electric bill somewhat. The downside of this project is that it got dust and insulation bits everywhere in my garage. I desperately needed to clean it. So, today's project was to get all of the stuff on the floor of the garage out so that I could clean it. I spent about 2 hours moving stuff out onto the side yard (which is now stuffed and cluttered), then pressure washed and flop mopped the garage floor. I still need to do the raised section around the workbench and sink.
I had to stop because I got tired and hungry and its 99F out this afternoon and I needed to cool off a bit. Which is why I'm sitting at my computer typing this post now.

Plus, I had to stop to go get my daughter, who was taking the SAT this morning.
So, the main garage is now pretty clean and I left the 911 outside under the car cover. The 74 FIAT X1/9 I put back in the garage. My current thinking is that I'll leave the 911 outside and put the 80 FIAT X1/9 in the garage so that I can keep it clean and finish the last bit of work on it before I sell it.
Meanwhile, I've looked at buying used kitchen cabinets to put along one side of the garage. There is a place close buy called Stardust that has them, but they still want a fair amount of money to my mind, and the cabinets are still fairly small. So, my current think is to gradually buy and install various metal cabinets for storage, ala Jack Olsen's 12 Ga Garage. I figure metal cabinets will hold heavy vehicle parts better and will look better in a garage than would old Kitchen cabinets.
I'm also considering just building a carport on the side yard, and then putting cabinets or shelves out there along the house wall. If I did that I would probably get rid of the shed because it takes up a lot of space. We'll see. A carport will likely require a permit, so that may not happen. In the interim I'm making do as best I'm able with what I have. I'm trying to rethink my garage space to maximize utility and the feeling of space. So, I'm not going to start moving stuff back into it unless and until I've decided it needs to be there or will serve a purpose.
Meanwhile, I'm definitely going to get rid of the garden tool racks on the walls. My thought was that I might get a broom closet and put them all in there. I can't really put them in the shed because (a) right now it's stuffed, and (b) it's not really tall enough. I haven't decided on the best solution for those yet but will soon.
I agree I don't need so many brooms. Honestly I don't even know how we got half of them. I just got tired of them being in the way (i.e, all over the house) all the time and put up that 8' rack just to keep them organized. I know at least one of them (along with a big aluminum dust pan) was left behind by a contractor doing work on the house. But whoever commented on that is right -- at least a couple of those should go away.
I also have a lot of stuff I've collected over the years that was going to either be sold or donated and just hasn't been. Since I'm back in my "purge" phase that's going to change soon. (It was a lot easier to keep control over this clutter issue when I had a pickup).
So, here's how the garage looked before I started:
And here is how it looks at the moment:
All the stuff piled on the 74 X is just there temporarily. You can't see it in the photo but on top of the front of the X is a bunch of tin that I got to run an exhaust out the side of the house for the dryer (when the roof was redone several years ago the contractor didn't reinstall the roof jack and it's just been venting into the attic). I was also going to use some of it to run the exhaust for the portable AC that I plan to set up in the garage to cool it for when I'm out there working, but unfortunately I bought 4" and discovered I need 5".
On the solvent issue, I don't know what is presently in the drum, and am concerned about mixing incompatible products. Otherwise, I like the idea of just running to the local tractor supply and getting 10gal to get things going. Except that the nearest Tractor Supply is clear on the other side of town and it would take an hour or so of fighting Phoenix traffic to get there. Plus, I really need to put it in the bed of a truck, instead of inside of the MINI or the Honda Odyssey.
So, next on the garage projects is removing all of the cleaning and gardening tools and racks, moving stuff out from around the bench and cleaning it, and deciding where to put the bicycles. Then I can start working on where to put cabinets and what to return to the garage now.
One thing that WON'T be going back into the garage is all of the paint cans I had along one wall. I kept those cans for years "just in case" I needed to do touch up. I thought even if the paint dried I could use the cans to match it. But the reality is that if I do repaint I'll likely change colors, and I can keep pictures of the labels to know what I have. So, the paint cans are going.
More to follow.