How to Make a Lemon Flea Spray: 5 steps (with pictures) – wikiHow. Thought I’d try this out and see how well it works. We live on the edge of the woods and all my cats (indoor only) and my puppy (indoor/outdoor) are all covered in fleas and miserable. It would cost a fortune every month for flea meds, so we’re trying this. I hope it works! I’ll let you know how it goes. What do you do for fleas on your pets?