Then drain it and run the engine dry to. I dont like to leave fuel in the tank over night. Nitro fuel just seems to pull water to itself. And as we know fuel and water dont mixx. Do you have any after run oil to put in your engine??? if not get some next time you go to the LHS.
If you are still on the break in period you probably don't want to put the fuel back into your gallon jug because of the fine metal shavings in the fuel as a result of the break in.
If your engine is already broken in you still should not recycle fuel because of these same tiny metal shavings as well as any filter oil or after run oil that will have gotten mixed into your tank while you wer running your t.