What to do about glass and trash in yard?

[Ian Hooper]

I just took possession of a property that I intend to hold as a rental. The house is ready to go, but the backyard has some issues. As I work in the backyard I find glass, sharp metal, and other garbage that could be dangerous if stepped on. The previous owner didn't maintain the yard, and the more weeds I pull, the more debris I find. My property manager and I are concerned about liability. 

Does anyone have any experience cleaning up a yard that has years of garbage in it? The way it is right now, I can't rent it to someone in good conscience.

Thanks.