Frontline spray ,i sometime just treat single ticks with a cotton bud and Frontline,o Tool tick pullers are the best way to remove them,but not always easy on a ferret.I also spray the sleeping boxes with frontline in the summer to control fleas,this year was really bad for mine for some reason,they are all kept clean with paper beds but i did have a lot of fleas,clean bedding every couple of days for a few times along with frontlining the box and treating the ferrets soon had them under control.