The answer:
If you used high pressure washing or a solvent cleaner and removed 95 percent of the gum, normally a high-alkaline, heavy-duty cleaner will finish it off. Mix according to directions and allow 5 to 10 minutes dwell time.
A pump-up sprayer works great for application. Scrub with a stiff broom, brush, floor machine or ... — Gary Clipperton,
National Pro Clean Corporation.
