Remove the ring of soap scum from your tub with liquid laundry detergent. For a really bad case mix dry laundry soap with water into a paste and apply to scum. Let it set for a while. It should come off very easily. Works on showers as well.
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To remove heavy soap scum buildup on clear shower doors without the heavy cleaning fumes use Avon's original Skin-So-Soft bath oil. Be sure to rinse well as the shower floor gets slippery. By Debi