There is no friction, so there is no non-conservative work going on. Since we have a gravitational potential energy here we need to set a 0 point: I'm going to choose a 0 point out at an infinite distance from the center of the Sun. (Or you could choose one at the center of the Sun, it works out the same. Both choices are commonly used and are equivalent in all respects.)
where m is the mass of the waste, M is the mass of the Sun, d is the radius of the Sun (remember we're measuring all distances from the center of the Sun here), and is the initial distance of the waste from the center of the Sun.
Since the container is "dropped" from rest
Solve for v.