[Richard L]

It is possible to use any washer fluid provided you don't leave it in the tank for months.

This is always a small amount of gycol in the fluid, the anti-smearing agent. Normally it won't present any problem until you don't use the fluid any more when you go on holiday the water/alcohol evaporates and left with only the concentrated gycol - it will become very sticky and started to become a problem for the water inejction equipment.