MJThe one drawback with your low tech method is that you certainly wouldn't be able to do the tailplane (plus, I'd be interested if you could reach the top of the rudder!!
). I suppose you could always get a pax to do the port mainplane (although some engineering work may be required if it were a female pax!
).
When at a UK club during training, I've certainly been provided with a B&Q garden sprayer to de-ice the aircraft. I've also been encouraged to position the aircraft to use solar heating to best effect!