We have lawns that are needing to be dethatched, but we can not justify buying or renting a vertical mower. Have any of you used those universal dethatching blades that bolt to rotary mowers? They look just like a mower blade with a spring at each end that scrapes the surface of the soil. I have used these on my own lawn for years with good success but not sure about using it on my clients' lawns. What do you think? Thanks!