My cat Snowey has really bad dandruff on her back. She has had this for over a year. I haven't taken her to a vet for a few reasons. One this doesn't seem to bother her. Two we don't have the money to take her. I am unable to work because I am ill. I bought her some cat dandruff shampoo and use it the other day on her. It doesn't seem to be helping. I am going to give her another bath soon using that shampoo. For her being 15 years old she is a very healthy cat. What should I do to help her get rid of the dandruff?