Circles should never be dismissed or forgotten about after ritual, but I don't feel that you have to be too formal about it either.

I reverse the order I cast the circle, ie, outstretch hands over head, bring them down, imaging the circle is going down to the middle.

Now take your hands so they point to the floor and bring your arms up until they are outstretched, imagining that the circle is coming up with them.

Take your hand and put it outstretched in front, walk round anticlockwise and imagine you are collecting up the ring in your hand.

Now thank the circle for its help and ask it to return to the earth to regenerate and do good work. Push your hand to the floor, palm facing down and imagine it shooting into the earth.