hy ted, i just finished : i washed it at a car wash, then i cleaned the rests with napkins + clean coolant; after it dried, i used napkins + desinfectant
i don't like the swamp that appears inside these tanks
i generally clean them 2 times / year :
... spring - summer : 1 nice clean, including tank wash, chuck apart & cleaning, cleaning behind the covers, coolant pump clean, etc
... near winter : only a quick coolant tank clean, removing as much of the swamp as possible, without emptying the tank
kindly