Are you trying to find a way to get rid of unwanted cardboard? You could just go ahead and fill up the landfills to overflowing, or you could try one of the following ideas. There are probably a dozen or more ways to get rid of cardboard; but for the sake of not being extremely boring, I'm only going to tell you about three of them.
1) An economic and environmentally friendly way to get rid of your unwanted cardboard, is by recycling it. Today there are many places that will actually pay you for your cardboard in the same way that they pay for bottles and cans. If you do decide to recycle, not only will you fulfill your duty to be kind to the earth, but you could also go home with a little extra spending money in your pocket.
2) A charitable way to get rid of your clean, unwanted cardboard, is by donating it for arts and crafts projects. You can call local childcare centers, schools, and churches to find out who might need it. Many places that work with children use cardboard to make signs or for other arts and crafts projects; it is much more affordable than poster board. If you do decide to donate your cardboard, you will be able to sleep well knowing that you have done your good deed for the day.
3) If you live in an area that has cold winters, and people still use fireplaces; you can get rid of cardboard by using it as a fire starter. The most important thing to remember if you plan to use your cardboard to fuel the fire; is to store it in a safe place away from your house, preferably in a shed not attatched to the house. Make sure that your cardboard is in a place where it will stay dry, and stored away from flammable liquids and gases. If you have an excessive amount of cardboard, you can share some with your neighbors; be sure to tell them about the proper way to store the unused cardboard until they are ready to use it.
I do hope that these ideas have been helpful; if not, you could just throw it in the trash, but then again if you do that, we just might run out of landfills.