Remove the screws from the back plate of your Macbook Pro
Place these tiny screws somewhere will you won’t lose them!
Carefully pry the back plate off starting at the hinge. Many times it will be stuck, however be patient and eventually it will come off. Do not force it too hard!
Use compressed air to blow off all the dust that has collected. If you notice large pieces of particulate, carefully remove them with tweezers.
Wipe down the back plate before placing back onto your Macbook Pro.
Make sure when screwing the back plate on that you don not apply too much torque to the screws! Just make sure they are snug.
If you need to purchase a new bottom case, you can do so here: