You can't turn them off. They are potentially lethal if they have been badly installed. A friend of mine had a shock through his SLX, probably from a crimped wire where the shielding had been breached. Search You Tube to see how seriously firefighters take the! Also see my post in "FAO Solar Steve".
I have cleaned them in the past like most WC's, but won't be touching them now till I get the right PPE.
All the best