cotton in the ear

[Karletto]

i bet it was asked before cos i noticed my grandpa is using it also.
so my uncle is recreational scuba. i noticed he puts cotton in his ears. what's the idea??
he said he pures a bit of it in the oil before.
but i didn't understand him if it's against earaches cos of the wind or against water driping from the ear but i doubt cos it isn't big problem.
hope you've understand something and sorry if it was already asked.

 

[..Sam..]

I think the reason people put oil in there ears is to stop wax build up which can cause equalisation problems.

Not sure about the cotton though.