In my classroom we use Franmar One Step Clear Emulsion and Ink Remover. We dilute it 4:1 with water. We pour about enough solution to cover the mesh (not the entire frame) in a photo tray and let it soak for about 5 minutes (agitating it cuts the time). Then we spray it out with a pressure washer. When we are finished we pour the solution into a brown gallon jug to store it until next time. It works quite well.
Right now we don't reclain enough to have a dip tank filled with the solution, but that is what it is meant for.
I know teachers that use the easiway system that you are talking about and like it. I use the franmar because it is cheaper.
I'm sure you could work something up out of some sort of tupperware/rubbermaid container and install a spigot close to the bottom for draining it. You may want to look into a couple instructions on how to install the spigot on sites about making rainbuckets. A little googling got me here:
http://www.naturalrainwater.com/make_rainbarrel.htm . I'm sure there are other/better sites and people on this forum who have home built their own dip tanks.
Dip Tanks 
