I noticed that the trunk in my Miata was slightly damp, which means water isn’t draining. Convertible cars have something called a rain drain, and these drains have filters on them to catch leaves from clogging them up. These rain drains are channels that catch the water that falls between the convertible top and the body, and run the water out through the bottom of the car. The issue is that leaves and other gunk often get in there also, so they need to be cleaned every 3 or 4 years. My Miata is 4 years old, so about time to clean them.

I lowered the top a little, scooted both seats all the way forward, then took off the side wall covers and the cover immediately behind them (behind the seats a bit). The side step comes right off, where the next cover has 3 of those little Mazda type clips.

Then you just reach back there and take the hard plastic filter off.

This part is super annoying, much easier if you have small hands. Moving the convertible top up and down will help your angle. This hard plastic filter probably has a few leaves in it, clean that out. The next part is pulling the sponge filter out. These were nasty on mine.

I took them inside and cleaned them good with hot water and soap, dried them out, then put them back in.

Then put the hard plastic filter back, button up the plastic cladding, and no more wet trunk. Here’s a useful video that helped me.