Giving a quote for a spring cleanup, and the lawn has a place (3'x3') where fertilizer spilled. The grass is dead. I need to repair, and wanted to know how to go about this. I thought I'd dig out the area down a couple inches, put in clean dirt and then one of Scotts grass seed/fert/mulch products. I want to make sure I get everything out in case ground is toxic. Any ideas?