Product review (4 stars): Can be worthwhile!
I've been aware of the Wonder Wash for a number of years; seems to me The Sportsman's Guide offered them in one of the very many catalogs they used to send me from the mid-1990's through about 2005 or so. I don't recall what they got for them at the time, but it was a nifty idea even if they wanted too much for me to jump on board and order one.

Fast forward a decade or so, and I run across one in a local charity thrift store I often peruse with an orange $7.00 sticker on it. Hmmm...

I looked it over and read through the instruction sheet that was inside along with the drain tube. When I was satisfied that it all made sense to me and that  it was both complete and intact, I decided now was a great time to buy one!

For what it is, it works pretty darned good.

I made sure the locking pressure lid was functioning and that I was able to close it as intended before I bought it. No problems there! About all I can say for the lid is that you'll discover that it needs to be REMOVED before the drum will drain to any significant degree. You'll get very little drainage, if you've used cold water, by just attaching the drain spigot. A trickle. You'll get a little more if the lid is loosened. To get a healthy stream of gray water from the spout, that lid needs to be OFF. The good thing about this is, you know the thing is water tight when it's air tight to the point that vacuum prevents it from draining. In a nutshell, the lid has a series of locking lugs. Line it up, drop it down, and turn to engage the lugs. It's maybe a tenth of a turn, until it stops. The handscrew on top tightens the seal. It is said that when used with hot water, the drum pressurizes; it is also warned that if allowed to cool without being open, a vacuum can result that would make the lid very difficult to remove. I suspect that plugging in the drain with the drum inverted would vent the vacuum, but I've never had it happen to me. They do warn not to store it with the lid clamped down. I follow that advice!

For operation, I suggest NOT spinning the handle. This causes several problems. One is that the centrifugal force throws the laundry inside to one end of the drum and it will STAY there. Not good. Turn it slowly. The slower the better. The idea is you want the clothes and the water to swish back and forth from one end to the other. One revolution per second may be a tad bit fast. You should hear and feel the laundry and water hitting one end of the drum, and then the other, over and over again. This is the agitation feature. The second problem is that spinning the drum fast will twist and contort the frame. You can even get the plugs over the screws in the joints to pop out, which isn't exactly desirable. If this happens, you're turning it WAAAAY too fast! Slow it down there, pardner!

The instructions state not to use boiling water. Excellent idea! That would soften the polymer drum, thus weakening it. Boiling water that comes into contact with your skin will probably soften and weaken you, too...

Follow the directions and use the correct amount of water. It would be easy to use too little, or especially, too much! A gallon and a half (6 quarts) is the most that should be in there under any conditions. That's around half full, before adding any laundry. A full drum (3 gallons, maybe?) will not help the laundering process and just puts that much more stress on the frame. It didn't say anything about detergents that I recall. Most anything should be safe. I often use clear Suave or similar shampoo, myself. A little does a lot, and the price is right.

The instructions do tell you how much clothing you can put in there at once. No, it's not a lot, really. I certainly would not put in more than you could hang up to dry after wringing it out! A little bit of laundry can use up a lot of clothes line! Depending on your circumstances, a few plastic hangers can be used. I do this if I'm in the basement and I don't want to take things outside. You can find a way to fit most any garment onto a clothes hanger, which in turn can be hung over a plumbing pipe, on a nail or cup hook driven into a joist, or whatever is handy. I'd advise NOT hanging wet garments on unsupported Romex-type Non-Metallic sheathed electrical cable, which shouldn't be installed such that you can hang things from it, anyway.

I get no value from suction cups on the bottom. I couldn't tell you how well they work. I set this thing on the concrete floor of the basement most of the time, and 'pin' it against the rim of the sump pit using my left hand and whichever one of my boots feels most comfortable while cranking with my right hand. The drum spins on its axis (tends to be upside down when unloaded and with the drain unattached) until water and/or laundry is added. Then the drum is bottom heavy, like it should be. When I attach the drain tube, it empties straight into the sump pit. I fill for wash and rinse from a hose bib installed right over the sump pit.

The crank handle is held to the drum pivot with a somewhat specialized cotter pin. Don't lose it, it may be very difficult to find a replacement! It looks like it's plated, but it acts like it's stainless steel; it's slightly attracted to a strong magnet, but not enough for the magnet to pick it up. The crank and drain spout conveniently store in the drum when the Wonder Wash is not in use, though I'd suggest you let the inside of the drum dry out good before closing it up! Should the frame eventually fail, I'll build a stronger one. Ditto for the crank handle. It's the drum and lid that really matter in this unit, and they seem to be all but bulletproof!

Great uses for this thing: T-shirts, socks, and underwear! I'm not sure sure about jeans and sweaters or sweatshirts, though I don't see why it couldn't work...it's just the wringing and drying that'll make those tough to handle. If you do anything that can be a bit messy...water based paints, anything 'bleachy', handle animals that can get messy when you're holding them, or whatever, this can be a handy way to save your clothing. If you've staged the Wonder Wash and a gallon jug of water nearby so it's ready to go, tear off your soiled shirt, apron, etc., toss on a clean one, then immediately dump the affected garment in and go. This is assuming it's a mess that will be 'OK' if an immediate dunking and rinsing in cold water will make the difference and you're a long ways from a washing machine. Work outdoors in the heat and humidity? You can take this, along with a gallon or so of water, to the jobsite with you. Take a clean shirt and a pair of socks, of course. Halfway through a hot and humid day, change your shirt and socks. Fill the Wonder Wash, rinse out your wet, sweaty shirt and socks, drape or hang them somewhere to dry, and they'll be 'almost clean' (not sweaty and smelly, anyway!) and at least mostly dry when it's time to go home.

Another possible use: If you load your own ammunition, especially pistol cartridges, this could be a nice thing to have. Spent cartridges have soot and lead residues from the primer inside of them, and dirt, sand, and grit from the range on the outside (as well as on the inside). You can put them in a vibratory tumbler with ground walnut shells or corncobs, but that is a NOTORIOUS source of lead contamination. Lead cleanup kits utilize a detergent that is high in phosphates, which converts the lead styphnate or lead azide residues into more stable lead phosphate. Such detergents aren't so easy to find anymore, but Cascade dishwasher powder has about 6% phosphates and is good for this purpose as long as you don't get the phosphate free formula! Wash and rinse your brass with Cascade and warm water in the Wonder Wash, drain (rinse the Wonder Wash out thoroughly!), and let the empty cases dry in the sun. Many will be clean enough to reuse right there. Or, if you still want to tumble them (perhaps after decapping the washed cases?), your media will stay cleaner much longer and the plume of dust that will result when you dump the tumbler out will be walnut shell or corn cob dust, with very little to no lead in it.