To prevent softening, plastic bottles should not be washed in which substance?

Plastic bottles are often made from materials like polyethylene and polypropylene, which can be sensitive to certain chemicals. Phenols are a type of compound commonly found in disinfectants and solvents, and they are known to have strong solvent properties. When plastic comes in contact with phenols, the chemical can break down the polymer structure of the plastic, resulting in softening and potential deformation of the bottle.

In contrast, while alcohol, pine oil, and chlorine bleach can have their own cleaning and disinfecting effects, they do not typically have the same immediate interaction with plastics that phenols do. Alcohol, for example, is generally safe for use on many plastic surfaces, and while some strong bleach solutions might cause issues over time, they are less likely to cause the same level of immediate softening as phenols.

Therefore, avoiding phenols when washing plastic bottles is crucial for maintaining their integrity and preventing them from softening.