The Japanese Society of Radiation Safety Management advises people to first clean off surface areas where radioactive cesium may have landed.
Large amounts of the isotope can attach to soil, roofs, walls, leaves and other plant surfaces.
Areas beneath gutters are especially prone to accumulated contamination.
Power washing these surfaces and areas is recommended, but that water should be collected and removed to keep the radioactivity from merely being moved around.
Denuding trees and other vegetation is also advised since they are likely to contain high levels of cesium.
Removing the top 2 inches of contaminated soil should also significantly reduce radioactive exposure, experts advise.