After my fiasco with the Walmart TLE, I found some concentrated all purpose cleaner at the Dollar Tree in the cleaning section that worked great. Made the huge ugly oil spot into a brely noticable spot. One dollar per 32 oz bottle, poured it directly onto the spot and scrubbed into the spot, rinse with good pressure water, and repeat as necessary. Took about two bottles to make the spot almost disappear. Worked good enough at the rental place that I did not get charged for the stain.
sig pic courtesy of GBALT05