Hello..... I'm here to the rescue

The cooker hoods which have a disposable filter need to be changed every 6 months

I always supply the custy with filter from B&Q, £15 and you get enough for 2 jobs.... But there are cheaper options also in B&Q....
I don't get much call for cleaning hoods because when I tell my customer that a new filter costs an extra £10, they tend to say they'll not bother :

Some hoods have a removable mesh filter which can be dip tanked but to be honest, It's easier to advise your customer to wash them in a dish washer every 6 months or so......