I have actually had good results by mixing Medihoney, Santyl and a small amount of hydrogel together.  Apply it to the wound (you can apply zinc around the wound to contain the mixture) and cover with adaptic.  The combination seems to really soften the slough making debridement a little easier and sometimes for the patient, quicker and less painful. 

This mixture seems to work really well on venous ulcers especially when covered with a foam and used under a compression dressing that is changed weekly.