You sound like a pretty new horse owner, are you? If you can I would invest in taking some lessons and getting a trainers help, while videos and written advice can help quite a bit hands on help has no substitute.
Start desensitizing her, she is far from bombproof i'm afraid but that is alright. Horses can overcome thier fears very quickly with the help of a person with good timing. Horses are pretty much scaredy cats by nature, some are naturally more anxious than others however.
This will be the same process for basically everything you desensitize her to. Start off in a rope halter if you have one, you'll have a bit more control this way. You will be using the approach and retreat method here. Approach with the scary object of your choice and wave it in the air around her side while standing at a 45% angle to her shoulder so you can't get run over. When she goes to move off calmly bumb her nose toward you so she's sidepassing and keep waving the scary object until she sands still AND relaxes (lowering her head and neck, more blinking, licking her lips, a big sign or cocking her back leg). The second she displays any of these behaviors (or just stands still for a while. At this point you're just rewarding the try) remove the pressure and rub with your hand.
When you can wave that object all around her start actually rubbing her with it on the topling first. If she moves off it's the same process and you release the pressure when she stops and relaxes. When she's fine with her topline move to her hindquarters, legs, neck then head.
To desensitize to the spray bottle it's the same ( have it filled with water though so you don't waste any product). Spray in the air, then eventually her in the same order. From there you can move onto an actual bath. Spray the water near her hooves and slowly move up. When she moves off keep spraying and when she stands still quit for the moment then go back to it.
If she's afraid of water puddles too i'll be happy to help.
Second, and this is a little pet peeve of mine, your mare may appear white in phenotype but there is no such thing as a white horse. I'd love to get a look at her however, i'm sure she's very cute.
Also, remember that horses learn from the release of pressure. So even when she is looking very scared about this. Do NOT take the pressure away, you will accidently be teaching her to be more scared of the object.