[header] How to clean walls with vinegar [title] Protect your floors. [step] Lay a dropcloth or towels along the baseboard where you intend to start. Ideally, your sponges shouldn't be dripping wet when you use them, so feel free to skip that part if you're confident in your ability to catch the occasional drip that may run down the wall. 
However : [substeps] Do keep some towels around just in case your bucket suffers a major spill. Play it extra safe and lay one out to set your bucket on while you work.