Herbal flea/tick collars and bandanas

In the spring, I started noticing that insects were very bad, and I had found a couple of ticks on my inside doggie, Zeus, just from running out to potty.  After reading online that lavender could be used as a natural flea deterrent, I decided to roll them into a cloth bandana, to see if it would help.  Zeus never got the first flea, and as an added bonus, we saw a marked difference in his behaviour.  He calmed down!!  However, he did get another tick or two...so, after more research, I used a combination of essential oils on a new collar/bandana, and he has not had a tick since.  The new combo is supposed to keep away all insects, including mosquitos and flies.  I am selling these for $5, and they will last around 90 days, about the same as a regular flea/tick collar.  I have read that they do not work well for cats, apparently cats are sensitive to essential oils, but in my experience it works very well for a dog!  I make them as a collar or a bandana, for those doggies who don't like bandanas!