I'm cleaning a really old shopping center. Store fronts only. There's a lot of gum in some areas. Is there anything (chemical) that I can put on it to make it loosen up from the concrete? I have a 3400 psi 4 gpm cold water. I don't have the money to invest in a hot water rig just yet. What can I do with cold water? I live in north Texas. Temps around here have been 100 degrees plus everyday. However I'll be doing this job at night. Thanks!