I am working on designing my outdoor set-up for my leopards. The area I have is about 10` x 10` my concern is about the soil that is there. The area is mainly used now for storing outdoor items.(lawn mower, garden tool, wash buckets,etc. I am sure the soil was also hit with a few dirty pails of mop water, and some drain off of spa water. There are weeds growing all over. Could I put fresh soil on top? and if so what should I use? I would just like to start it all over, with new plants and weeds. Top soil,sand mix, potting soil????