Dampen a strip of litmus paper, also called indicator paper. Use tap water to dampen it rather than saliva. This product contains phenolphthalein, which should not be ingested.
Walk around the refrigeration system slowly while watching the litmus paper. If you notice the paper turn pink or red, stop walking. This color change indicates an ammonia leak.
Dampen another strip of litmus paper after you have sealed the leak. Hold the paper near the area of the leak and wait several minutes. If the paper turns pink or red again, the refrigeration system requires additional repairs.
Grasp the end of a sulfur stick opposite the wick.
Light the other end of the sulfur stick with a lighter or match.
Walk around the refrigeration system slowly and watch the sulfur stick. Pass the stick over and around the area where you suspect the ammonia leak. If the sulfur stick begins to emit white smoke, this indicates the presence of ammonia.