If you are using a smaller portable diesel generator for example a 1000 watt model, which usually most cases is more practical, you would be using 1.2 gallons every 5-8 hours depending inside the load. This comes to $5 every 8 hours ,or $15 for every 24 hour period.
Studies proven that a V-6 automobile engine uses approximately 5.5 gallons of gas for every 90 minutes it operates. What this translates to is if you would run a 750 watt inverter, you should recharge a 120amp battery every 120 minutes by idling the car for 10 mins. This means that you could get 36 hours of use from a 750 watt inverter 1 side gallon of gasoline. This equals a $3.00 fuel price every 24 hours if gasoline is being $4 a gallon.
My guess is, hangover remedy came along with one of two words mental conclusion on the assessment of a particular potentially valuable asset, "junk" or "scrap".