If you have inspected your surface and feel that the infill is contaminated, we need to determine to what extent. If it is larger debris such as leaves, twigs, stones, seeds, etc then regular Power Sweeping will be sufficient to rectify the problem. Power Sweeping removes debris from the surface which Drag Brushing alone will leave behind. If the problem is with finer contaminants then you may have noticed a hardening of the surface or silt deposits after heavy rain. In this case a Revite^® or Rejeneration^® will be the answer.