After all the methods you tried out, how can you be sure if fleas are still around or not? Here is a simple method you can use. I found it while I was hunting down fleas. Jeff Hahn, Assistant Extension Entomologist of University of Minnesota wrote it.
The easiest is the white socks test. Wearing a pair of white socks, someone walks slowly across rooms where are fleas are suspected. Fleas are attracted to the vibrations from the walking and the warmth of the person and will jump towards the ankle. Their dark colored bodies show up plainly against the white background of the socks.
Besides that, you can also try this method.
Place a shallow pan of water in a room where they are suspected and put an Alka Seltzer tablet into it. The carbon dioxide that is given off attracts fleas. Put a couple drops of dish soap into the water to help prevent fleas from jumping back out of the pan.
If your efforts are successful, then you won’t be able to see any fleas.
You can get the whole article here http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-Nov0101.html
