permission pitch

I'm hoping this helps some one out it's kind of a one foot foward pitch beginning, made for you to build your own you know get you newcomers started kind of thing "are you the home owner my name is (insert name here) im not selling any thing its just ive noticed your house as through the neighborhood and it looked as if it was built in (insert date here [prior research of house helps] ) My hobby is metal detecting to find old coins, and the best places to find them are on places like your [yard/field/etc]. I always seek permission from the property owner beforehand and assure them that I use a technique that leaves no holes in the ground, and I remove all trash I might find. I was wondering if you wouldn't mind if I detected your yard."