Laundry facilities are available in Cape Town, throughout South Africa, Johannesburg, Maputo, Swakopmund, Victoria Falls, Dar es Salaam, Zanzibar, Kampala and Nairobi. Often for a small fee, you can have your laundry washed on your behalf. Most camps (excluding remote camps) have hand-washing facilities.
A handy tip: you can buy a small box of eco-laundry detergent from your local camping store or once in Africa.