All I can tell you is my experiance !!
Intermediate (Junior high) seems to produce the most coins and the occasional usually lower grade jewelry Items,, grade school has very little to offer but sometimes I have found things that I know were either show and tell Items or went to school without permission.
High school,produces some of the best stuff I have found as far as schools go. I usually try to keep up on the school activities, football games, dances, festivals,things like this, and always keep in mind that schools are a living thing many times what is there now has probly replaced something else in the past,look through the old year books at the library the older the better, check and see what happened there during the silver years, where they held graduation, where the larger activities took place , old baseball fields, football fields, soccer fields, practice fields, all of these things can make an hour or two much more productive.
once you find early 60's cents or wheaties, keep track of the depth, this will be a relitive depth for most things within that time frame, I figure 5years back and 1 year forward for dates.
Hope this helps !!
Ummmmmm Nohope !!
Congratulation on your pillardome !