I AM BUILDING A TUMBLER . BUT I AM USING AN ELECTRIC ICE CREAM MOTOR AND TOP TO CLEAN BOTTLES ON THE INSIDE . PUT IN HAND FULL OF CUT COPPER SOME BAR KEEPERS AND WATER , USED COTTONBALLS AND ZIP LOCK FOR A CORK , SEAL IT WITH ALUMINUM DUCT TAPE . TAPE THE BOTTLE TO THE WHITE ICE CREAM LID USE CARD BOARD FOR THE NECK SUPPORT (SHOE BOX WITH A HOLE IN IT . LET IT RUN FOR DAY OR TWO AND THE INSIDES A WHOLE LOT BETTER. JUST USING STUFF LAYING AROUND WHILE I FINISH THE REAL ONE . OATEY TEST PLUGS REALLY SAVED ME . ALSO USING A FREQ DRIVE TO CONTROL MY RPMS WITHOUT THE HASSLE OF ADJUSTING PULLEYS . THE MOTOR , FREQ DRIVE , ROLLER BARS , DRIVE BAR , PILLOW BLOCK BUSHING , PULLEYS AND BELT PLUS THE FRAME METAL WERE ALL DISCARDS FROM MY JOB , ALL I HAD TO BUY WAS THE PVC TUBE AND PLUGS (HOME DEPOT) . CUT THE COPPER MYSELF FROM SOME OLD 14/2 ROMEX AND I STILL HAVE TO BUY SOME ALUMINUM OXIDE . ALSO 1000 GRIT SAND PAPER TAKES SOME OF THE CRUD OFF . TRIED HYDROFLOURIC ACID (HAD SOME LAYING AROUND FROM CLEANING MY A/C LAST YEAR . IT WORKED 50/50 BUT NOT AS GOOD AS TUMBLING AND AND SAND PAPER . I WILL POST PICS AFTER I FINISH .