I remember asking once, we don't we just shoot our surplus trash off into the sun and was told that by the cost of launching it outweighs the benefits. Fair!
But what about all of the old satellites and space stations? Why don't we just send a giant magnet around the earth once or twice and then slingshot all that space junk into the sun and thus giving all science fiction writers (when they return from their strike) a plot point they can no longer use in their film scripts?
Seriously though, without the cost of breaching the atmosphere, this seems really cheap to pull, why don't we do this? Why isn't this a standard thing?
It’s not about speed, but energy. Virtually all satellites are gravitationally bound to Earth. Think of Earth’s gravitational potential as a funnel. The satellites sit somewhere on the walls of the funnel. Now, next to the Earth’s funnel, there’s. much deeper funnel: The Sun’s gravitational potential. But between where the satellites are and the point where the Sun’s potential starts attracting them is still a big "hill" or wall separating the two funnels from each other (the top of that hill is the Lagrange Point L1). So to get a satellite out of Earth’s potential to a point from where it could “fall” towards the Sun still requires a large amount of energy.