Mind Fuck Tuesday: Psychometry Experiments Your Input Needed

So, y'all know my strongest specialty as a psychic is my psychometric skills (ability to read objects and hone in on those who have handled them). Well, recently while working on a book and reading abandoned sites, I came across a site that had been burned horribly--completely charcoal on the surface. I went through the entire house, found not one item I could read. The first time in my entire life, nothing came to mind at all. It was both blissful and scary.

That being said, I realized that there are two possibilities here; the surface contains the information I gather or the surface became too porous to read. I have a harder time with things like paper and plastic but an easier time with things like stone and metal.

That being said, I ask for your input in possibly ways I can experiment to find out if the information held in an object is only on its surface layers and, if so, how deep?

I'm curious to see what you smartie pants might come up with.