>"Bleaching may not do much after so much exposure and time."
Be very cautious on the use of chlorine around food. As excited as anyone wants to get about BPA, other hormone mimics, and generalized organic-chemical nastiness, chlorinated organics are typically worse than un-chlorinated organic chemicals. Spill 1,000 gallons of gasoline and you might pay me $300,000 to clean it from the soil and groundwater. Spill 1,000 gallons of TCE, TCA, or PCE and you'll spend millions (and still not be done).
Use chlorine (and Bromine and Iodine) to kill infectious organisms. Do not use it as a cleaner. HDPE cleans up very nicely and very safely in a standard dishwasher. Those very alkaline detergents are tough on your skin, but tougher on bacteria. And they are completely dissolved in the rinse cycle of the washing machine.