Make a homemade flea killer by placing water mixed with sudsy dish detergent in a white tray and shining a dim light on it at night, advises The Daily Puppy. The warmth of the light attracts fleas, which end up in the water and drown.
Borax and salt can be used as homemade flea killers, reports FleaGuide.com. Both substances dry the outer part of the flea, leading to its demise. Sprinkle borax on floors, carpets or furniture, ensuring that it gets into all the cracks and corners. Leave it on overnight, and vacuum in the morning. To use salt to kill fleas, first grind the salt into a powder, then sprinkle it on floors, carpets and furniture. Leave it in place for 24 to 48 hours before vacuuming it.
A homemade concoction that kills fleas on pets is Dawn dish detergent mixed with apple cider vinegar, according to FleaGuide.com. Combine a bit of apple cider vinegar with Dawn dish detergent and warm water, and apply it to the pet. Allow it to remain on the pet for 10 minutes before rinsing. Follow up this treatment by using a flea comb on the pet to remove dead fleas. Repeat the treatment as needed.