Rusty Water Bucket

Sure nice to see an influx of members here with lots of advice to share. I have a waterer now a few years old that has the galvanizing wearing away exposing the steel which now is rusting. This is the type of waterer that is basically an upside down bucket over a right side up bucket. I have used pickup truck liner under my mower deck to preserve the mowing deck and I'm wondering if this might extend the useable life of the waterer. Is it safe to use this way? Maybe I should just let it rust in peace.

Rust in peace, nyuk, nyuk, good one! Could you oil it with food grade oil? Olive oil or mineral oil? Or paint it with Tremclad? I have a 45 gallon barrel cut in half as a water barrel and same thing, rusting. Water is orange. Hope plants don't mind rusty water.