I just roll mine up and let the stuff fall into the water - BUT- I quickly get my hand skimmer on a pole and then scoup the stuff out of the water before it saturates and falls to the bottom.

As for warming the pool, the solar cover is somewhat of a misnomer. The pool would gain more solar energy without the cover, but it would also loose heat due to evaporation and wind loss, thus the cover helps maintain the heat as opposed to really adding heat.