This DIY is on a 03 - 08 Corolla which has a cabin air filter behind the glove box .
Part Number # 88568-02020
You remove the screw in the first photo to make this diy very easy .
Once that is remove then you squeeze the corners on the inside of the glove box and pull towards you.
Then you will see the cover for the cabin air filter once remove then you can gently slide out the old one not causing any dirt to fall in the blower motor .
You can vacuum if needed . In this case I bought the cabin air filter I bought has charcoal to help keep the air clean .
Put every thing back and you will feel a better breeze now from your a/c.
To prevent thins from getting dirty quick when you drive recycle the air when the a/c is on and do not park under trees .