Plastic

With the resin unnamed, nothing can be assumed about migration, and the claim brands most often substitute for disclosure is "BPA-free". That claim rules out exactly one chemistry: BPA is a building block of polycarbonate and of the epoxy resins lining metal cans. It says nothing about which resin was used instead, what catalyst or stabiliser residues that resin carries, or what temperature it can take. For our ratings, two questions survive the uncertainty - does the part touch food, drink or skin, and does it get hot. An unnamed plastic in a cold, brief-contact position is documented and left alone. An unnamed plastic in a hot path is treated as the weakest link in the product.

You cannot know a plastic's service temperature without knowing the resin, and the spread across the common ones is wide enough that guessing is useless. Where an unnamed plastic sits in a boiling-water or hot-oil path we assume the worst case and say so in the product's contact-path notes. The fix is a named resin, not reassurance.

Look for a number from 1 to 7 inside a chasing-arrows triangle moulded into the part. 1 is PET, 2 HDPE, 3 PVC, 4 LDPE, 5 polypropylene, 6 polystyrene, and 7 is "Other" - a residual bucket holding everything else, including polycarbonate, copolyesters such as Tritan, nylon, ABS, acrylic and PLA. That is why a 7 on its own tells you almost nothing. Two further traps. The codes are defined by ASTM D7611 for identification only and are explicitly not recycle codes: the standard states that the code does not imply the article is recycled or that systems exist to process it, and bars recyclability claims from being placed next to it. And the marking is applied mainly to packaging, so an appliance tank, a lid or a length of tubing is often unmarked. When there is no code, ask the manufacturer, in these words: which resin, by name or code number, is each part that contacts water, food or skin; is it virgin or recycled feedstock; what is its maximum service temperature; does it carry any fluoropolymer or PFAS-based coating; and can you share food-contact compliance documentation (FDA or EU 10/2011). A brand that makes the part will answer. A brand that rebadges someone else's often cannot, which is itself an answer.

Without the resin you cannot know whether a part is dishwasher-safe, UV-stable or oil-resistant, so the only general rule is to watch the surface. Hazing, crazing, chalking, softening or a persistent plastic smell mean the part is past its service life and should be replaced.

Mixed and unmarked plastics are the hardest fraction to recycle: the US recycled 8.7% of all plastics in 2018, and code-7 and unmarked items are essentially never separated at a materials recovery facility. Assume landfill or incineration. Black plastic is a specific case worth knowing about - it is hard for optical sorters to see, and a 2024 study found brominated flame retardants in black household items at levels consistent with recycled electronics feedstock.