Simple methods for cleaning PCBs

A clean PCB is important for reliability. Printed circuit boards sometimes accumulate dust or other contaminants that need to be cleaned. A dirty PCB may interfere with the proper functioning of its intended design. 

Whether your boards are dirty due to exposure to their operating environment or due to improper packaging or protection, proper cleaning methods must be used to improve reliability.

Dust consists of material suspended in the air. It is complex in nature and usually contains a mixture of inorganic mineral materials, water-soluble salts, organic materials and small amounts of water. As SMT components become smaller, the risk of failure due to contaminants increases. Research clearly shows that dust makes boards more susceptible to moisture-related failures such as loss of surface insulation resistance, electrochemical migration and corrosion.

Use extreme caution when cleaning PCBs. ESD precautions should be taken into consideration, and it should be done in a dry place with the power disconnected. If incorrect methods or procedures are used for cleaning, the board may not work at all.

For dust, the best way to remove dust is to blow the board clean with compressed air. Be careful of sensitive areas that could cause damage. A toothbrush is another tool that can be used to remove dirt and dust.

Boards with residual flux must be cleaned with a saponifier. For hobbyists and engineers, the most common is wiping alcohol. A toothbrush can be moistened with alcohol and can be used to scrub any flux. Note that if your board was soldered with no-clean flux, it will be difficult to remove and you may need to use a stronger cleaner.