When creating a For Sale listing, include a statement requiring a specific reply in the subject line of replying emails. For example, "Must put 'Purple Monkey Dishwasher' in Subject line of your response. All others ignored." This reduces the number of spam replies that are sent and eliminates opening email replies from those who are not genuinely interested.
I use our local Volunteer Fire Department parking lot to sell items. Safe for me, plus, a buyer would probably get nervous if they had to find our S&B, hidden back in the woods. I've had much success buying and selling on CL, but I always take precautions. It's not all idiots.