Nikwax Rug Wash is a wash-in cleaner for all horse rugs / blankets.
 
Rug Wash safely revitalises insulation & water-repellency.
 
If a breathable waterproof rug loses its water-repellency, it will suffer a severe reduction in its ability to breathe.  This will lead to a build up of condensation on the inside of the rug so the horse will become clammy, cold & uncomfortable.