also meths will help remove insects in summer.
Does it get them drunk to the 'mellow' stage when they just want to wander of home?
Maybe, but I am always shocked by the amount of fat that comes out of insects, this is always more noticeable on my motorbike visor, where one insect strike can make it hard to see out of one eye, and if you wipe it it can spread even more.. no wonder birds get fat in summer. When I used to wear an open face helmet and RAF type goggles I had a big fat bee hit my cheek at about 60, made a tidy bruise ( could have been worse if it had been flying away from me and I hit the end with sting in it first
Insects hit a sloping windscreen at an angle and may bounce off, but with a vertical visor that splat straight into it and spread out..
On my motorbike I once had a big fat woodpigeon resolutely flying towards me down the centre of the road, as I watched to see if he would swerve he didn't seem to be deviating as he got closer I realised we were on a collision course and jinked sideways, the pigeon hit my handlebar mirror and there was a burst of feathers, - other bikers have had pheasants do the same flying trick but luckily missed at the last minute, a heavy pheasant could do you a lot of damage and I doubt meths would help ....