About the only things they have left are household chemicals, liquid petrol and stove-gas cylinders.
I assume cop masks stop things like bleach fumes if they make them immune to teargas, so playing Chemical Ali may be hopeless right off the bat. Wouldn't really recommend that route anyway; you're more likely to toxify yourself and the family trying to bathtub-brew something you don't understand the chemistry of.
Petrol will happily burn anything it coats but when they break out the rubber bullets or pepperballs, that's it for getting within throwing distance. A 3-man sling (like the ones sold for water balloons ) can send a full bottle of water several stories in the air but with questionable accuracy. Meaning it's up to you not to land one on Grandmas roof instead of a pigmobile.
Nobody can deny the power of a gas explosion on a civilian building but they're heavy as fuck, making them useless for rapid 'field operations' and getting the fuel-air mixture right for an amateur is largely gonna be a matter of luck.