Damp cloth for cleaning the tubes, as for the reflectors have you thought about stainless steel clean - even though they are not stainless it should be ok as its not an abrasive cream, more of a smooth cream.
Hi I use white vinegar and paper towel, pour a little vinegar on a couple of squares of kitchen paper and it easily cleans the deposits or build up if any water from the tank has splashed or tarnished the reflectors, I think its the chemical deposits from EI. Then buff the lamps and reflectors to new! Up until now my open T5's and enclosed Arcadia Luminare are looking as good as new. Regards Colin.