I use a liquid cleaner that's a drying agent once a week on mine, and
xfngr
they've been fine. You put the liquid in each ear and then put a cotton ball over the ear opening, and gently swab the ear. They don't really like it, but it's quick and not too much work. I'll try to remember to look at the bottle I have at home and I'll tell you what brand it is.
I would buy a clear liquid if possible though; the last brand I bought was a bright lavendar color (because of the gentian violet - I think that's the drying agent), and it spilled on our brand new light colored bamboo wood floors and stained them purple!
The color had to be sanded out of the floor...