Test test test.
Honeycomb fabric repels dust through the concertina effect of opening and closing the blinds. The more you use your blinds, the cleaner your fabric will be.
They can also be gently wiped with a soft cloth or vacuumed on a low setting with a brush attachment.
Translucent honeycomb fabric can also be washed in water up to 30º with a mild detergent.
Blockout honeycomb blinds are lined with aluminium foil and are not suitable for immersion in water.