We did that when we were in high school. On the old rigs you just bent the whole metal tab up. Then we would fill the resevoir with used motor oil. Yes, that is totally stupid and irresponsible but when I was 16 it was funny. Also knew a guy in college that spliced the line (hose) and routed it through the firewall to dump just under the drivers side dash. He would fill the resevoir with vodka and juice. Needless to say he was obviously a dumbs**t, but I admire the creativity.