    # File lib/rbot/core/utils/httputil.rb, line 654
      def remove_stale_cache
        debug "Removing stale cache"
        now = Time.new
        max_last = @bot.config['http.expire_time'] * 60
        max_first = @bot.config['http.max_cache_time'] * 60
        debug "#{@cache.size} pages before"
        begin
          @cache.reject! { |k, val|
            (now - val.last_used > max_last) || (now - val.first_used > max_first)
          }
        rescue => e
          error "Failed to remove stale cache: #{e.pretty_inspect}"
        end
        debug "#{@cache.size} pages after"
      end