In article om,
"Jay Honeck" wrote:

Carrying water around in "The Mighty Grape", and sitting at my gas
station pumps while pouring water and gas into a beaker, and shaking
it, is just too much of a pain. People in line behind me must really
wonder what the HECK I am doing! :-)
If I can get away with simply dropping a tablet in the beaker, I will
(a) eliminate the water, and (b) speed things up considerably.

After performing the test, and the fizzing commences, pour the contest
of the test tube into your tank. When they ask you what you are doing,
tell them you have discovered a magic tablet that allows you to put
water and the tablet in your tank and make your own gasoline. What they
saw you doing was testing to make certain you had the correct
proportions.