I guess you could message it into their hair and skin and wrap them in a warm towel. I would do that right before a bath. I would not use the salmon oil though -would be stinky

this whole process would be messy too, I don't think I would do it if they had lots of hair. Someone on here said coconut oil rubbed on the hair (while dry) and left on was good for flea treatment, but I have never heard of this before and I would be afraid the oil would rub off on furnature and carpets.
But, most on here give it orally. I think start out with 1/8 teaspoon each day and work up to 1/4 or 1/2 teaspoon. Bonnie just licks it up. She thinks it is her treat for getting her hair brushed and top knot put up.