Flies - skin so soft oil works well but its oily and attracts dust, I will usually cut it with water then add a drop of dish soap to take away some of the oiliness. Or white vinegar water and again the soap just a drop it helps it bond and after the rain or a quick spray with the hose they get clean
Hooves- Plain mineral or corn oil around the coronary band for moisture. Bleach for thrush works well. You can make a hoof packing out of gauze or a big hand full of cotton balls soaked with preparation of your choice then take a plastic bag cover the foot, cut the bag about an inch below the top of the hoof and duct tape it up dont be afraid to use alot of tape the more you use the better it will last especially on the weight bearing parts. Good old fashion Epsom salts and a bucket
Sores/wounds- neosporin or the generic triple antibiotic ointment, Peroxide make sure to not use very often can cause proud flesh . Antibacterial soap works the best just rinse with plenty of water. To make a bandage in a pinch use a ladies pad and smear ointment on to the pad then place on a hand towel put pad on to would and wrap towel around leg the secure with a ace bandage and a bit of duct tape. For swelling you can rub leg down with icy hot wrap leg with plastic wrap then a hand towel then ace bandage and a piece of duct tape the help sweat the sweling . Epsom salt soaks
Flaky Skin- The yellow mouth wash the cheap kind the horse doesn't care how it tastes but the mint or other flavors can draw flies so make sure its plain. Another one my family has used for years is baby oil and iodine/betadine. Just a table spoon or so on a full bottle of baby oil. It works on flaky skin, rain rot and fungal infections of the skin.
Internal ailments- I just call the vet always ask first but if you can get some mineral oil down them thats always best in the case of colic especially if he cant get there right away.
Fun story please don't try this!!!
My grandma swore by a a 3 foot section of hose and a bit of mineral oil to lubricate. She would attached that to a regular hose and run it up her horses hind end and turn the hose on. I have seen it work every time on every mild to moderate colic case she ever got her hands on she usually had a bit of bute paste and the started the messy business but ill be damned it she ever called the vet for colic!