Agree on the veneers applies with chemical glue and presses. The glue isn't water soluble, and the amount of heat needed to begin to make it let go would ruin the sample. It's possible to use an industrial glue softener after stripping the finish, bout that stuff is very toxic, and often not sold to the public, so might be a moot point.
Best luck is with natural (animal) based glues, usually pre WWII, and steam. Poor condition old dressers, lesser dining tables (veneered tops), sideboards are great candidates for harvesting, the rest can be firewood. They'd likely end up thrown out, so at least this re-uses such furniture finds completely.