One of the more annoying aspects of my 1994 Mazda Miata was the center console armrest’s hard plastic cover. Whenever my elbow touched that cover, it just plain hurt. So, I decided to fix the problem. I bought some supplies from Amazon, and got started.
The first item on the shipping list was a package of NU-Foam. This poly-fil is really great, it is compressive, however even when compressed down, it still has a lot of give. Perfect for providing a firm arm support that still has cushion. 
The other product was a sheet of genuine leather, plenty to cover the arm rest. The piece I bought was 1 foot by 2 foot.
We will attach the leather to the plastic cover using a staple gun. Make sure you have a good quality staple gun and staples. I don’t think size is very critical, however the gun needs to be strong enough to pierce the plastic. I suggest practicing with a few staples before you try and attach the leather.
The installation process is actually super simple. First remove your console cover, it comes off with a couple of phillips head screws. After removing, clean it up and test fit your material. 
Cut a piece of foam to fit the top of the lid. Don’t skimp, it is easier to start with too much and trim it back if you get too much.
Now is the only tricky part, cut the leather to overlap the top of the cover. Starting at one side, firmly staple the entire side. Then carefully stretch the leather across and fasten the other side. My suggestion is to stretch tight enough that the top of the cover is firm, however still has noticeable give, this is what will make it comfortable for your elbow to rest on.
The final two sides will be a little more challenging. You have to stretch and tuck the leather so that you do not have any large creases on the top of the armrest. Don’t be surprised if you have to pull some staples and reposition, just be patient and take your time. When you are done, it should look like the picture below. Now, go and enjoy your new arm rest!
