[MaSnaka]

White vinegar will remove water deposits and it works great on bathroom fixtures (chrome) and you can let them soak overnight with no ill effects. If what your removing is water deposits and not drywall mud this should help. I would try it diluted with water 50/50 first and work to a stronger mix from there. I don't know how it will react with your sidepipes. Perhaps try it in an inconspicuous area first. Lemon juice is an acid again be carefull on the metal. CLR cleaner works great diluted with water to remove water deposits and I use it on the boat to remove the water spots on painted fiberglass, works great. Be careful with the metal, not sure how it will react. Remember to rinse this stuff off when finished. Strong chemicals.

John