GOLD is a very large and very thin balloon–up to 100 meter diameter–which when inflated, increases aerodynamic drag on space debris at low earth orbit by a factor of up to several hundred. Increased drag means shorter times for an object to de-orbit, described (in a no-doubt best case) “from centuries to months.”
While GOLD or GOLD-like technologies seem to have plenty of merit to help avoid new debris problems–just attach the package to launching space systems like rocket bodies that are debris creators– it also claims to be able to mitigate existing debris.
This would be done by co-orbiting with the piece of space debris and robotically attaching a GOLD device to the debris. That scheme seems a bit… further out (so to speak).