A. Beneath the surface the worms are aerating the soil, a good thing, but they push the mix of soil and natural secretions to the surface leaving slimy deposits. It’s best to brush these away on a dry day. To help prevent a lot of worm activity it’s best to keep the lawn clear of leaves and other decaying matter. There is a product called CastClear you can use as a suppressant but this is applied in the autumn.