Wool Felt Grizzly Wool Felt Upper - Use a soft brush to remove any dirt or debris that has accumulated. For heavier dirt build up, spot with a damp cloth and brush gently. We do not recommend that you apply chemicals or soaps to the wool felt-this could compromise the natural breathability and strength of the felt. Cork Latex Footbed - If you intend to use the Grizzly in inclement weather conditions, we recommend that you use a cork protectant/sealant on the footbed at least once a year. This will help preserve the natural cork latex from breaking down prematurely.