How to inspect used tires?

Only driven on Sunday

       That was Gary’s comment when he was selling me a set of P235/65/16 tires, snow studded tires, I though it is funny, who will drive on these tires only on Sunday.
It was a very nice set, no weather cracking, or any visible damage to the tire side wall, and actually they look really driven on Sunday, he might be right.
The things a bout buying and inspecting used tires, there is a chance you over looked something and the funny part is to discover it in front of the buyer, look here, there is a nail, that is what happened when I was shown a buyer a set of P215/70R15, how did I miss this nail, I do not know; but it is there, and I better do something.
We got it out, it did not look like it went through the tire it was very much side way.
I apologized to the gentleman and told him to go to this particular tire shop I deal with and they will mount and balance the set for a very good price, and if anything wrong with the tire they will patch it, with no additional charge on his side, and he may call me with any concern, and let him make the decision. He bough them, and has a peace of mind that I will be there if he needs me.
There is nothing more powerful than the truth, say it, let it out, do not hesitate a second, that a sale will not happened, if you say it.
A very nice lady call me for a set of P195/70R14, with a Dodge Neon rims she want it for her son’s car, she tried first to tap the price down; but I was firm on it, the price is just right .
The tires tread was excellent; but one of the steel rims was really rough, the other three were okay rims, any way, she liked the set and her son approved it, yes they are the right one. I told her a bout the rim which has some rust on it, she said, little paint will do it, and bought the tires and rims....what a deal.