I would just keep topping the gas tank up every couple of days. As in when it gets down a 1/4 of a tank or so top it off and dilute the tank.
I had an old Dodge beater truck that would suck the brake master cylinder dry in a hard stop (bad power brake booster and leaky master cylinder I guess). The engine would knock and a nice white cloud of smoke would come out the tail pipe, but it ran that way for awhile before I scraped the whole truck.
Reminds me of the story where i guy showed his wife how to check the oil and where to add it if needed. He forgot to show here the oil and she added washer fluid to the crankcase…
EDIT: texases brings up a good point…I will have to play chemist on that one.