I do that now kinda. I put coins from the year it is in the bottom of footings. Has to be nice and shiny. They demo some concrete, but other concrete is there for many many years, sometimes centuries. That's the beautiful part about footings as well, many times they will tear a house down to the ground and build.a new one on the existing footer. Happens all the time, so my nice, new 2022 quarters coild be hidden for centuries. Not quite the same as you, but I'm not going for deception.