If you keep some level of hygiene in the kitchen that you run and not the servants, then these are indispensable... you must have them.
What you must do though is wash the one you extract from the packaging for use, really well. You must wash out the 'softeners' that are in it... and then you are good to go!
They soak up anything! BUT remember, they works not just like cloths but also like sponges, so germs can sit in them and stay there. You will need to every now and again disinfect them in boiling hot water and a Dettol solution (that's how I do it). That way they'll last longer!