Ivermectin is considered a safe and effective method of removing ticks and mites for many kinds of animals. In fact you can purchase liquid Ivermectin at some farm stores....
Please note I think its a VERY BAD idea to acquire it and try do it yourself. It is something that should only be done by a trained professional.
You have to know exactly how much to use for your snake (Based on weight), it also has to be injected subcutaneously. Depending on the size of the snake you may also have to dilute the liquid Ivermectin which from what I remember isn't as simple as adding a little water. If your snake doesn't react the way it should to the drug things could go very bad very quickly. At a Vet the doctor has things he or she can do if something unexpected happens, he will also be able to react and quickly diagnose any problems that occur.... In essence what I'm saying is, this isn't as simple as "give the snake an aspirin and call me in the morning".
Also, Ivermectin has been known to cause neurological symptoms in some species of snakes, it also can breach the blood brain barrier in other species of snakes. (All though BP's and Boa's are not among the species on that list.)
Please remember I'm NOT a vet... I just have a good memory, I read a number of articles on Ivermectin during a mite scare a few months ago. (I got worried because my Boa spent 3 days solid in his water bowl soaking). Turned out to be a hide issue, but I fixed that and its all good now =D
That's just what I remember about it, someone else may be able to shed more light on the subject.