I run a service truck and do some mobile pm work along with alot of other things. I guess I'm just trying to find the most efficient process possible (and the simplest). When the boss was running a truck he brags that he only used "empty 5 gal buckets that got tied down in the back. Thats all you need..." My idea is in part due to Willie's detailed (and brilliant) post about his water tank. If I had a barrel/tank, could I hook up regulated air to top and have a fitting and hose at the bottom to evacuate/drain it? This part doesn't seem too tough. I have seen products for the manufacturing realm that use a venturi type air vaccuum to move things. Would it work to have a changeover to block off the air source for pressurizing and then be connected to a vaccuum source to suck oil out of (you name it). I know most people use a double diaphram pump and get along great, BUT that costs money and the powers that be will give me a flat NO. What do you guys say?