while re-fitting my bathroom i had to change the bath taps and U bend,so i crawled under the bath (just) with very little spare room,the trap had one of those little drain nuts on the lowest part so i got the top of a deoderant spray and drained the trap into it when the top was full nipped the nut back up and with my left arm reached out annnddd...empted into the bath !!!!! 10 minutes and 20 fills and empties later i realised the trap was not a ten gallon one ......a star is born.