Hi, the most easiest way to keep air con running in my opinion is to keep using it ;-) cant remember what they say but make sure you use it every 2 weeks or something, as if my memory serves me right the gas acts as a lubricant also, so even in the winter keep using for a little while to keep things running smoothly, think its meant to keep the air con compressor running free, ive had them before where air con compressor is siezed and been told because people only ever use in summer, im sure someone else will give you some tips also :-)