code: protected void handleDeadSlop(SlopStorageEngine slopStorageEngine,
                                    Pair<ByteArray, Versioned<Slop>> keyAndVal) {
          Versioned<Slop> versioned = keyAndVal.getSecond();
          // If configured to delete the dead slop
          if(voldemortConfig.getAutoPurgeDeadSlops()) {
              slopStorageEngine.delete(keyAndVal.getFirst(), versioned.getVersion());
  
              if(getLogger().isDebugEnabled()) {
                  getLogger().debug("Auto purging dead slop :" + versioned.getValue());
              }
          } else {
              // Keep ignoring the dead slops
              if(getLogger().isDebugEnabled()) {
                  getLogger().debug("Ignoring dead slop :" + versioned.getValue());
              }
          }
      }
docs: Handle slop for nodes that are no longer part of the cluster. It may not
  always be the case. For example, shrinking a zone or deleting a store.