i use butler creek covers and they work very well.mine have a little tab on one side and you just touch them and the cover pops open.for cleaning you first need to remove any solid particals like dust,dirt etc,if you try to wip this stuff off with a cloth you will scratch the lens coating.with a camera lens brush gently wipe the particals off.after brushing if the lens are still foggy or smeared use a eye glass or camera lens cleaning fluid.with a lint free cloth gently wipe off lens.if to much pressure is used you will wear into the lens coating.always keep good covers on the scope becouse the more this type of cleaning is done the sooner the lens coating will wear off.