So the cats have been spending a lot of time outside, now that they're bigger, especially at night. One downside to this is that they pick up fleas and carry them in to the sofa, beds, boys, and just about everywhere else in the house. We thought we were keeping on top of it, periodically dusting them down with DE (diatomaceous earth). The dogs all have flea collars, but that doesn't work so well on cats.
Anyway, it turns out that we didn't have it under control at all, and now the house is kind of infested! So we have been attacking the problem.
For a start, the cats are now living outside on a permanent basis (we may let them back in after the rain season, as we don't have fleas here in winter). Secondly, we washed all blankets, sheets, curtains, clothes, and cushion covers, adding vinegar to the rinse wash to kill the eggs. We then washed all the floors with vinegar water, and dusted any fabric that couldn't be washed with DE, like mattresses and the sofa.
We are also putting out plates at night with warm, soapy water in them. In the center of the water, we light a candle. The warmth and light attracts the fleas, and then they drown in the viscous water. These traps are picking up the stragglers that we've missed, and the problem seems to be resolving itself. If I don't do another blog on the subject, it means we won!