Demodectic mange (like Rafi has) is a whole different thing and not contagious but there's lots of great info on the board about treating it. For a spectacular recovery check out this video
about Audrey a little GSD from Harlan rescued by a former board member.
Sarcoptic mange (the contagious kind) is pretty common around here but very easy to treat. If you are fostering dogs with sarcoptic mange, I recommend the following:
When you bring home the dog, quarantine it away from all other animals and handle it as little as possible yourself. When I first bring one home, I use rubber gloves and a lab coat. That may be overkill but it makes me feel better.
Sarcoptic mange mites are arachnids (similar to chiggers if you have those in CA) and they burrow in the skin. Dog sarcoptes is species specific and is not the same thing as people sarcoptes (aka scabies) so they can't complete their life cycle on people and are not contagious among people. However they can and will
bite you even if they can't reproduce or spread and you will end up with itchy swollen welts, often around your beltline. Ask me how I know this.
Anyway, you keep the dog isolated. My preferred treatment is with the topical flea/tick/heartworm preventative Revolution. It works quickly and is far less toxic and labor intensive than nasty dips. Instead of once a month you give it every 2 weeks for three doses.
In addition to the Revolution, I recommend washing the dog regularly with a medicated dandruff shampoo. It exfoliates the skin and aids healing, in addition to hopefully knocking off a few of the mites. After bringing home the dog, I start with the bath and then apply the revolution.
Your vet may also give you antibiotics or antiyeast medication because mange can often create the stage for other secondary infections.
I consider the dogs to be okay for integration by the third treatment but I tend to be very conservative and picky about disease control and the dogs I'm fostering are often small dogs and easier to keep quarantined. Some people feel fine after a month of treatment, some people feel okay shortly after the first Revolution. I'm not recommending that, but people do it, apparently without problem. In all cases, I strongly recommend that all other
animals in the house use Revolution as their monthly flea/tick/heartworm preventative when you've got residents with mange. That way, in the unfortunate event you transfer a mite from the affected dog to your own pets, they're probably covered.
I have treated a lot of dogs with sarcoptic mange and - knock on wood - have never transferred it to anyone but myself (see above) and that was before I knew what it was and how to deal with it.
Also, in the unhappy event that one of your other dogs does contract it, it starts with itchy motheaten patches and goes from there. There is absolutely no excuse for these people who wait for their dogs to become completely bald and covered with sores before they notice there's a problem. It doesn't not spead over night. I've watched it spread around shelters and the first sign is usually itchy patchy spots around the ear margins, face, lower legs, or belly. If left unchecked it can take over the entire body, leaving them bald and miserable, but that takes weeks even months.
Hope that helps! Feel free to ask if you have any other sarcoptic mange questions. Been there, done that!!