What method should be used to check for a gas leak?

Using a soap and water solution to check for a gas leak is a widely accepted and effective method due to its simplicity and reliability. When you apply the soapy solution to the joints or connections where gas might be leaking, any escaping gas will create bubbles in the soap mixture. The formation of bubbles at a particular spot indicates the presence of a gas leak, allowing for easy identification of the issue.

This method is favored because it is non-invasive and does not pose any risk of igniting a gas leak, which would be a significant concern with other approaches. While using a gas detector is also a valid method, it may not be readily available in all situations, whereas a soap and water solution is accessible and easy to prepare.

Using a cloth to check for leaks doesn't provide a reliable means of detection. Additionally, using a lighter would be extremely dangerous and could lead to explosions, making it an inappropriate method for leak detection. Thus, the soap and water solution remains a safe and effective choice for identifying gas leaks.