I took my reel apart to clean it and there was some grease on the brake discs. They are supposed the be dry aren't they?

This depends entirely on what make of reel you have.  Some manufacturers recommend drag grease for the drag washers and some recommend no grease on their drag washers.  The difference is in the material they use to make the drag washers.

Just to double check you are talking about the drag right?

As I understand Daiwa and Shimano drags are greased, and Abu are dry. With the multi stack Abu drags you can grease them, to make them a little smoother especially in start up.

I've greased plenty of stock Abu Carbon Matrix drag washers with good success.

You just don't want OIL in the drag.

It's an ABU Swimbasser. Thanks! I guess I should have said that in the beginning.

Greased or dry is fine. I like to grease most of their drags but leave the Premier/Skeet dry.

I haven't tried greasing the Premier/Skeet since it only has one drag washer. It may function fine, but I haven't tried it.

Abu what?  Abus generally should be left dry.

An ABU 6601.

Some carbon washers come with dry lube, but if you're satisfied with the performance of the drag there's no harm in a light coat of good drag grease.

An ABU 6601.

Dry.  Though if they're fouled, I recommend giving Smooth Drags a call, and getting replacement Carbontex washers.  If you want smoothness, and soft slippage, lightly lube with Cal's Grease, or go dry for maximum stopping power.