Choosing the right products to use in a cleaning gun depends on your specific cleaning needs and the surfaces you are cleaning. Here are some popular and effective products commonly used with cleaning guns:

1. All-Purpose Cleaners: Versatile cleaners suitable for general cleaning tasks on various surfaces such as vehicles, engines, tools, and household items. Examples include Meguiar's D101 All Purpose Cleaner and Simple Green All-Purpose Cleaner.

2. Foaming Cleaners: These cleaners produce foam when used with a foam cannon or foam gun attachment, ideal for cleaning vehicles as the foam helps lift dirt and grime. Examples include Chemical Guys Honeydew Snow Foam and Adam's Car Shampoo.

3. Degreasers: Used for removing heavy grease and oil buildup from engines, machinery, and industrial equipment. Examples include Purple Power Industrial Strength Cleaner & Degreaser and Super Clean Tough Task Cleaner Degreaser.

4. Interior Cleaners: Specifically formulated for cleaning car interiors, including upholstery, carpets, and dashboard surfaces. These cleaners are often pH-balanced to be gentle on interior materials. Examples include Meguiar's Carpet & Upholstery Cleaner and Griot's Garage Interior Cleaner.

5. Disinfectant Cleaners: Used for sanitizing surfaces to kill bacteria and viruses, commonly used in healthcare facilities, food service areas, and other environments where hygiene is critical. Examples include Lysol Disinfectant Spray and Clorox Clean-Up Cleaner + Bleach.

6. Detailing Sprays: Provides quick cleaning and a glossy finish for vehicle exteriors, suitable for light dust and fingerprint removal. Examples include Meguiar's Quik Detailer and Griot's Garage Speed Shine.

When selecting products for your cleaning gun, consider factors such as compatibility with the surfaces you are cleaning, effectiveness in removing dirt and grime, safety precautions, and environmental impact. Always follow manufacturer instructions for dilution ratios and safe use of the product with your cleaning gun to achieve the best cleaning results.