My mixer is clean as the day it was made about 30 years ago.
I bought it from a guy who kept it perfect inside and out.
He told me he kept the outside parts like the stand rubbed down with grease to keep concrete from sticking. There wasn't an ounce of crete on this thing when I bought it and it was used plenty.

I find a couple shovels of clean hydro rock and water spun for a few minutes does the trick of preventing any buildup inside.
I can set the angle so the rock reaches right to the lip as she spins.

Thanks. I'll clean it, then put Crete-lease on the outside.

What is hydro rock?

Mercedes

hydro rock is just clean screened to size crushed rock used as drain rock. You will see it everywhere used for paths. I have several sizes but use 3/4" in the mixer.
It's what I have on the ground under the mixer as well 5-6 inches deep so I'm never standing in a pud of concrete mud, it flows down under the rocks leaving the rocks on top clean. So I just dump the mixer and carry on, no mess.

You can use a chisel on the lumps in the mixer BTW.

I've had good luck cleaning up the mixer when I finish making a batch of hypertufa with the pressure nozzle on the garden hose and scrubbing with an old toilet brush. If something gets built up because I got lazy with my cleaning, I have bashed it (carefully) with a rubber mallet and the clumps fracture and come off. I think I will try that water/hydro rock tho!!

Hi Debra
I just dug a 6" deep pit about 5x5' square and filled it with crushed rock. My cement mixer sits on that.
I just scoop a few shovels of the rock into the mixer when I'm done then dump them right back on the ground. All the cement water just goes straight down leaving the top clean.
It solved the problem of my dogs tracking concrete mud everywhere and having it dry on their feet.

My work space has 12" of 1" crushed rock for a floor. I'm pleased to see that this might be the best choice I made. The boat barn is slowly turning into a tufa studio.

Mercedes

Mercedes I think you made the right choice. A lot of times mixers don't get cleaned properly because all the water creates a big mud puddle under the mixer so people stop too soon and don't do a good job. With drain rock you can do a great job because the water is not a factor on the ground.