swallows second brood

I left a window open in a garden shed,and the swallows promptly built a nest on top of a tin of paint! Gave me a perfect excuse to put off painting an awkward corner, but meant couldn't use the shed all summer. However ,looks like the 2nd brood won't be long now: mum and dad are catching insects dawn to dusk.
With abit of luck I will be able to lift the paint lid,use the paint ,and put the tin and nest back for their use next year.