The front parking lot at North Penn High School was a busy place Saturday as Montgomery County held its second household hazardous waste collection of the year there. About 700 vehicles pulled in to drop off unneeded motor oil, automotive batteries and cleaners as well as other items that can be described as flammable, poisonous or corrosive. Latex paint, alkaline batteries, smoke detectors, medical waste and air conditioners were not welcome though. Old computers and electronic devices were also turned away. Special collections are scheduled for them. The next one is at Indian Valley Middle School on April 21st while another household hazardous waste collection is on tap for May 12th at Upper Merion Middle School in King of Prussia.