I've found that a long plastic wedge or screwdriver works good. Remove the lamp and unplug. Insert the wedge through the opening towards one side and pry down while pulling at the same time. There are tabs on the top of the box that keep it tight behind the dash. Do both sides and it slides right out. Then slide the white lock up and remove the access door to the filters. Replace them in the same position. You'll be amazed at how dirty they are.

Bill
1991 300E