I Love the smell of that mix of gas/balsa that my big planes have. Dont know what makes it or why.

As for your spill problem, It happens to me all the time as I transport landscaping tools in my truck. Most of the time, if I leave the windows open and the smell is gone. The gas will evaporate quickly, but the oil leaves the smell. If I cant stand it anymore, I will wash/vacuum the carpet with baking soda and water, after a pre soak/removal of dish soap/water mix. Works great for me.