Just a bucket with a rebar cage type construction inside, water and soda crystals. I just pulled the boat impeller part out and gave it a wipe. Before and after pics attached. People have to remember this is set up, switch on, have a coffee, do some odd jobs around the house, have some food, sit n read the paper with a coffee, switch off, pull it out to check and look at in wonder, then repeat. Finish off with a rinse and a wipe. Not as fast as attacking it with an angle grinder but much more chilled and the kids are impressed with all the science stuff. Looking good so far!