Our garden is a little bigger than that, say about 3/4 of an acre. We worked it out that we have removed over 30 tons of assorted rubbish from the land over the last 15 years. AND we are still finding stuff. For instance today I found a mole hill, on top of the soil was part of a toy gun, some broken glass and a Shipham's Salmon paste jar.
Keep up the work and be sure to keep taking pictures of your progress. We did not have a camera when we began and regret it a lot that we have no real record of what we did.