I am thinking of putting down some concrete ONE part epoxy paint(not the rustoleum or quick Crete garage floor two part epoxy with flakes). I have removed linoleum & I have some old black hardened & dried adhesive. When I drip some water on the concrete it beads up as if the concrete is sealed. Can I use the concrete floor primer on top of this adhesive or will I have to sand the adhesive & concrete surface down before pairing?