Before tackling a particleboard cleaning project with any wet product at all, give it a thorough sweep. A fine-bristle hand broom for a shelf and a traditional, wide broom for a floor will get into the thin crevices of the composite board and release dirt and other grime. This will go far to reduce how much liquid cleaning is required, saving the board considerable stress.
Using a sturdy hand brush with strong plastic or natural bristles, go over the particleboard surface again. Small, circular scrubbing will release even more dirt from the board. Sweep the surface clear, and repeat the circular dry scrub two or three times. By now, the particleboard will be noticeably cleaner. With regular maintenance, dry scrubbing and sweeping will keep your particleboard clean.
Wiping down particleboard with a water and vinegar solution eliminates odors and stains without harming the material. Use this method sparingly, as any moisture can potentially warp the particleboard. Make the solution by combining 1 part vinegar -- any kind of clear, white vinegar is fine -- with 4 parts water. To apply, dip a plastic scrub brush into the solution, shake off excess and use small circular scrubbing motions on the particleboard. After completing a section, immediately dry the area with a clean towel. Do not let the solution sit on the board after the scrubbing.
When particleboard is new or freshly cleaned, you can apply a sealer or primer to prevent future problems, especially mold growth. In a well-ventilated area, or outdoors, spray or brush the primer, sealer or another stain blocking solution onto every surface of the particleboard. Leave the particleboard untouched for several days so the seal locks in and the fumes of the solution evaporate.