I usually just let them out in the backyard in thier nappies with a hat and sunscreen. I'm trying to teach Yasin to use the loo so sometimes he just goes starkers.
If Yasin wants to go into the courtyard to play with the neighbours he has to put some clothes on.
I'm a bit uptight about the midday sun so between 10.30 and 3 I keep them under cover - they are allowed on the patio but no further.
If they get really grotty I just get the hose out and make it into a fountain and Yasin runs around under it which gets him nice and clean. By next summer Imran should be old enough to enjoy getting clean under the hose too.