★★★★★
Citrus Peel Infused in White Vinegar
★★★★★
Citrus peels have two organic chemicals called limonene and linalool which kill all stages of the flea's life cycle.
Just pour a 1/2 gallon (or really as much as you want, cause it can also be used for general household cleaning too) - of white vinegar into a large glass, covered container and throw in whatever citrus peels you have - oranges, grapefruit, lemon, lime... doesn't matter which or how much...as long as it's completely covered by the vinegar. Stir or shake it up every once in awhile and give it a week or two. Leaving it in sunlight will accelerate the process.
I use the solution, once a week, as a final rinse (don't rinse it off) after their baths. The citrus chemicals kill any fleas they may have picked up and smell of the vinegar, though not detectable to us, once the dog is dry, repels the fleas for the rest of the week.
The solution can also be put in a spray bottle for occasional spot treatment and it can even be used as a cleaning solution around the house!