If it looks unpleasant, I clean it, but I do it for aesthetic and olfactory reasons, not particularly for hygiene.
There's a lot of hysteria these days about having every surface antiseptically germ-free. Most of it, I suspect, whipped up by the makers of cleaning products. My view is that the immune system, like any other organ in the body, needs exercise or it gets flabby.
It might be a coincidence, but since I started to take a more casual approach to "all those billions of bacteria crawling over every surface"

I've felt fitter and stronger. I used to come down with every bug that was going around - colds, flu, sore throat, stomach upset... I've had one mild dose of the sniffles in the last two years, and haven't had a day off work sick for over three.
