Bokken that are used in light contact or hard contact training applications, such as in paired exercises, should be oiled before use in order to resist the terminal pressures of internal stress caused by bokken hitting bokken, bokken hitting jo, etc. To properly oil your bokken, take a fine grade sandpaper (e.g. for removing varnish) and gently sand off the glossy finish only. Then place the bokken in a tube that can be filled with wood oil, or wipe the bokken with a cloth soaked in wood oil. Follow all instructions for the wood oil you are using. Wipe off any excess oil prior to use. To prolong the safe and long use of your wooden weapons, we suggest that one always do the following: Oil your wooden weapons properly, inspect them for possible fractures prior to use, do not use them to strike against unreasonably hard surfaces, and do not keep them in temperature and/or weather conditions that are deteriorating in nature to wood.