Engine grime can be difficult to wash off of your hands. If you don't have a hand cleaner handy, your kitchen cupboard probably contains a solution. Reach for either a vegetable or olive cooking oil and spread a dab over your hands. Rub your hands together, then wipe off with a paper towel. Cooking oils will also help remove oil-based paint from hands and arms.
When shopping or air conditioners, look for seasonal energy ratios (SEER) over 12 for central air conditioners and energy efficiency ratings (EER) over 10 for room air conditioners.