Please learn to use punctuation.
There are numourous brands that will give the horse a shiny coat. Look for anything silicon based, and I believe they now have a large number of non-silicon based products that have the same result. Maybe a good wash and conditioning will be aquequite tho, since it is just a clinic.
Ilovemymare - hair spray should be ok, but condition the mane before using it, and wash it out as soon as you are done, and condition it again. I've used pink spray on my mare's rump before, and had no problems doing this. My sister on the other hand, was too lazy to wash her horse after, and it ended up staining him and he was blue for a month. Both horses are grays.