Expert shares three methods to remove black oil from stainless steel utensils
A Hong Kong housekeeping expert has outlined three ways to remove industrial black oil from new stainless steel tableware, after a parent's online query went viral. Toxicologists warn the residue can contain neurotoxic compounds, and doctors advise avoiding 200-series steel for food use.
A Hong Kong housekeeping expert has shared three effective methods to remove industrial black oil from new stainless steel utensils, after a parent's online post about the problem went viral on Threads.
The parent, using the handle "dinosaurs_ni," said her child's teacher had told her to wipe the bowls with cooking oil. After doing so, the paper towel turned "blacker and blacker." She wrote: "It seems like I can never wipe it all off," and asked for help on how to clean them properly. She added that she had tried using dough to absorb the residue but, perhaps because she had applied too much oil beforehand, the dough could not pick up the black marks.
The post sparked heated discussion, with many experienced users offering tips. Some suggested using more cooking oil to wipe several more times, letting it sit overnight before washing. Others recommended boiling the utensils in water with sodium percarbonate for a few minutes, then washing with mild detergent, or using baking soda, white vinegar or stain-removing powder.
During manufacturing and polishing, factories use stamping oils or polishing oils to reduce friction between metal and moulds. If pre-shipping cleaning is inadequate, industrial black oil remains on the surface. Toxicologists warn that such lubricants contain organic compounds with neurotoxic properties. If not thoroughly cleaned before use by young children, there is a risk of ingesting toxins.
Housekeeping expert Lulu recommended three methods. First, "oil dissolves oil": spray a little cooking oil onto the stainless steel utensil and, using the solvent effect, wipe inside and out with kitchen paper until no black marks remain. Second, dough absorption: mix flour and water in about a 2:1 ratio to form a dough, then roll and press the dough over the utensil to absorb oil trapped in crevices. Third, white vinegar boiling: add white vinegar, sodium percarbonate or baking soda to a pot of water, place the stainless steel items in, and boil for about 30 minutes. Whichever method is used, the final step is crucial: wash thoroughly with mild detergent and a sponge, rinse off all residue, and air-dry upside down.
Separately, nephrologist Dr Yan Zonghai warned that 200-series stainless steel contains 5.5 to 7.5 per cent manganese — about 2.75 times higher than food-grade 304 stainless steel — posing serious food safety risks. He said 200-series utensils are not only more prone to rust but may also release high levels of manganese. Long-term ingestion of manganese can have neurotoxic effects, damaging the nervous system, liver and kidneys, and potentially affecting brain function, leading to weakness, dizziness and coordination problems.