My kitty loves to be flea combed. The fleas and old fur go into a coffee can with dish soap and water. Then the lid goes on the can. The bugs are dead in minutes. This has become a daily ritual which
she loves. After 13 years still no sores or tumors on her from toxic
repellants. Put a bare light bulb under a chair at night(turn it on of course)and hang it over a bowl of soapy water. The fleas are drawn to the warmth and perish in the soap. Flush bugs down toilet. Repeat as necessary. Hope this helps. Dave