How to clean filters from extractor fan?

[frakkinup]

Above our hob we have a fan with very fine mesh filtered. I wipe these regularly with a vinegary cloth and remove them about once a month for washing with soap and hot water.

Despite my best efforts they're still quite greasy and dirty-feeling. There are 3 layers of very fine mesh and stuff gets trapped, which might be a result of my wiping as well.

How can I get them properly clean?

I would be interested too as I basically do the same and mine sound the same type as yours. However I put mine in the sink and wash with hot soapy water and then leave upright to dry out overnight. Mine soon feel greasy again so I guess I need to wash every week.

However, if anyone knows of a better way to clean them I would be really interested.