gathering the ashes of the deceased
Refers to the Japanese funeral custom where family members use chopsticks to pick up the bones and ashes from the cremated remains and place them into an urn.
After the cremation, the relatives performed the bone-gathering ritual.
Compound of 骨 (こつ, 'bone') and 拾い (ひろい, 'picking up'), the nominalized form of 拾う (ひろう, 'to pick up').