I’m looking for general advice on any potential issues that I should be aware of, and advice on materials to temporarily cover large public areas (like sidewalks or streets) with eco-friendly, non-toxic, easily washable marks — something bright, bold, and large-scale, but fully removable and harmless.

a spontaneous, temporary art intervention that could be cleaned off quickly if needed, not permanent, not damaging, not about vandalism. I’ve looked into things like sidewalk chalk, chalk markers, spray chalk, pigment powders, etc., but I’m searching for the best materials or methods that can cover large areas fast. I've seen graphiti writers use a wide spray nozzle that would be perfect if it could be applied to a temporary material.

If anyone has experience with this kind of public art or knows the best materials, I’d appreciate any guidance or suggestions. Thanks in advance