"1 part cleaner to 1 US gallon of water" is a ratio, not a specific measurement. It means that you need to use 1 unit of cleaner for every 1 US gallon of water. The "unit" of cleaner can vary depending on the type of cleaner you are using.

Here are some examples:

* For liquid cleaners: 1 ounce of cleaner to 1 US gallon of water.

* For powdered cleaners: 1 tablespoon of cleaner to 1 US gallon of water.

* For concentrated cleaners: The instructions will specify the dilution ratio (e.g., 1:10, which means 1 part cleaner to 10 parts water).

Always follow the specific instructions on the cleaner's label. This will ensure that you get the correct dilution and that you don't use too much or too little cleaner.