I sprayed the interior of a double-wide trailer with Coverstain once, due to the fact that it was caked with nicotine tar—even after scrubbing, it was so brown. We stayed a little late to finish up—probably left around 8:00 pm or so. I came back to do finish coat the next morning, opened the door, and was literally bowled over by the toxic waft of fumes that assaulted me. When we were done, though, that place smelled so much better.So what are you spraying that requires an oil primer? It may be fine to run through your machine, but spraying out a whole house will be nasty and a bit of a fire/health hazard.