Mesh filters in cooker hoods

They're normally made of aluminium mesh, which dissolves in dishwasher detergent. Maybe your old ones were made of something else?

Having said that, I've washed them in the dishwasher occasionally, between lettings. They have a large surface area which can trap an enormous amount of grease, and they need about twice the dose of detergent that a full dishwasher would normally have (at least, if you only do them occasionally).

Many of them do seem to be aluminium. Mine are stainless, and came with directions to use the dishwasher to clean them.

If they are aluminium (most are) dishwater detergent causes them to become oxidised and turn a dull and swirly black in parts.

In your previous house either they weren't ali, or were black from day one and therefore you never saw them any different.

Derek G

Havent a clue. They were shiny and went in the dishwasher and remained bright and clean.

In message , SS writes

I clean ours in the sink with hot water and Oxyclean. All the grease just floats off.