I used a large garbage can to flush mine,and figure several things.
That the garbage can was a pain to move after filled and the only way to dump it was to hook up pullout and hope the thing would fall off.
. that being said I think I will get one of those rubbermaid tubs. If you run an out board in a tub the water hats up and gee in the kitchen sink hot water cleans better than cold water.(breaks salt deposits better). and two the exhaust contains oil in it that I think helps lube the water impeller that other wise would never get any and would help prevent it from drying out from the air...