Normal rabbit ear wax is soft and yellowish in color. There is not much and usually you would never see it. If you are seeing crusty material in or on the ears, it could be ear mites. They can easily be seen under a microscope and treated with Revolution. If you are seeing a white creamy substance that could be pus from an infection.
Here is some general info on rabbis http://www.veterinarypartner.com/Content.plx?P=A&A=673&S=5 don't hesitate f there are any more questions.
There really is no care he needs to do for his ears. If you cleaned in his ear with a q-tip and found this waxy material it may be normal for him and was there all along. If there is so much that it is erupting out of his ears there may be something going on- mites, an infection, something causing irritation. What do you mean by he is an older bunny? I have seen rabbits at 12 and 13 years old be still healthy. If he is overweight that may be due to diet. Pellets should not be the primary food for house/pet rabbits. Hay and green leafy vegetables should be most important. Pellets were invented for rabbits raised for meat so they would gain weight fast. We don't want our pets to be fat, I assume people with pet rabbits are not planning to eat them.
The link I sent you before has a lot of good information on diet. Let me know if this answers your concerns