One "trick" with EOR is to use it and keep it in a sealed container. I bought a gallon of it over a year ago. After use, I filter it through a coffee filter. It takes quite a while to filter as it is thick and takes time to get through the filter. I still have about 2/3 of that gallon left and it still works great.
I have cleaned hundreds maybe even thousands of tools. Some were rusted from sitting in the weather for 4 1/2 DECADES. I don't pour the obvious junk in the filter so some does get poured out after each use. I use various size Tupperware containers to soak the tools. Lid on. I have left some for weeks. Its good stuff IMO. Sometimes it leaves a little too much black oxide on the tools, but they look better than they did, that's for sure!