Mite treatment for rodents

I'm picking up a few natal rats to get a breeding colony going. The breeder ordered in some new adults for fresh bloodlines and it seems that the new one may have mites and now there is a slight concern that the ones I'm getting may too.
His vet has him treating them with a spot on medicine which I assume is like the meds dogs get for fleas. This type of meds can remain in the system for many months and I don't want that. So what else can I use for treating mites? Is imovectin (sp?) safe? I won't be feeding any natals for 2-3 months but I don't want any poison to remain in their system.

You can buy ivermectin in paste form (horse dewormer paste) and give them a dose the size of a grain of rice orally. Just make sure that you empty the entire tube and mix it together throughly. Dose them with that once a week for three weeks.

Or, I prefer to buy revolution (www.petshed.com) in the kitten or cat formula and you give that to them topically. One drop between the shoulder blades. That works for a month and will completely rid your rodents of mites. You can chose to dose longer if you need to (which I have never had to do more than one dose).

The ivermectin is also sold as a liquid to give topically, but I believe that has to be purchased from a vet. The paste form is kinda a pain because it doesn't always work.

Thanks. I talked to the breeder and revolution is what he is using.