The best I have found is undiluted muratic acid...just spray it on for a few minutes and wash it off with the water hose...It will not leave a shiny finsh, more like a satin (i guess), but it cleaned 3 yrs of crud off my tubes. If you really have to have that shiny new look...well I guess a lot of alum polish and much much more elbow grease...
Oh, I dont need the polished look. Just wanting to get the hard crud off.
The best I have found is undiluted muratic acid...just spray it on for a few minutes and wash it off with the water hose...It will not leave a shiny finsh, more like a satin (i guess), but it cleaned 3 yrs of crud off my tubes. If you really have to have that shiny new look...well I guess a lot of alum polish and much much more elbow grease...