Scarify

verb

1. To remove thatch (build-up of organic matter on the soil) from a lawn, to dethatch.
2. To make scratches or cuts on.

   "A combing tool is used to scarify, cross-scratch, or score the surface of a scratch coat or undercoat of plaster."

3. To harrow the feelings.
4. To scar.
5. Denude, or lay waste to.