Initial Cleaning

• You'll likely be cleaning your stones outside when you find them. They're probably going to be dirty in some way, so it's a good idea to give them a rough cleaning when you pick them up. If you can rinse it in water, then this is ideal. A light scrub with a toothbrush or similar brush is also a good way to dislodge any dirt. If it's a more delicate stone, you may want to use paintbrushes.
  
  

Full Cleaning

• The full cleaning will get your suiseki stones ready for display. This type of cleaning is much more thorough than the initial cleaning you do on the spot when you find your stones as that's a more practical clean to stop your clothing or skin getting dirty. This round of cleaning is for presentation. Wash with a high pressure stream of water. Soak the stones in soapy water for at least five minutes. Very dirty stones may need to be soaked for multiple days.
  
  

Cleaning with Acid

• Acid is one way to clean suiseki stones. This is potentially dangerous and requires much caution. Water should never be poured into acid, the process should always be the reverse. Acid should be poured extremely slowly into water. The area you are working in must be properly ventilated and wear goggles and a face mask to protect yourself from the fumes or potential harm to your eyes. If still acidic, neutralize the water using baking soda until the pH level is around seven.
  
  

Rotary Brushes

• When brushing a stone by hand, you may have trouble dislodging some of the more stubborn soil. In this case, you can use rotary brushes, which are usually in the form of attachments to drills. These brushes should be made of wire or hard nylon to brush suiseki stones. It is still necessary to wear protective gear, such as goggles, to protect the eyes from loose pieces of stone and soil.