The best thing to keep water running down you arm is a cheapo rubber bell boot 
A huge horse massager. It’s too heavy to hold up and my horses respond better to me just massaging them by hand anyways.
The fancy $30 fly spray that is supposedly great for horses is the same ingredients as the stuff in the aerosol can at tractor supply co for $12
I have more polo wraps than I should admit to and haven’t used a single pair in years….
White lightning is Oxine. You can buy a gallon size of oxine for way less $$ and it will last you years.
I have a plethora of soaking boots; none of which I use, because I use gallon size baggies and this one giant boot that I swear was made in 1812.
The fancy ‘pony soap’ that’s $25 doesn’t clean any better than the $6 garnier fructis shampoo
Betadine or no tear shampoo is easier to use than the stuff designed for sheath cleaning and less likely to cause irritation if you don’t get it all out for some reason.