I know this is overkill but you can theoretically contract salmonella from your fishtank,
so the correct clothing from a health and safety point of view would be arm length gloves, glasses and face mask.
with the use of a hand sanitiser afterwards
the glasses and face mask are to stop any splashes from hitting eyes or mouth
no using mouth to get the syphon going either
and what p44 said
P.S. no i will not write up a tank cleaning procedure or operational manual for you