The perfect tool is another QD attach as a dummy QD to prevent any pressure from building.
Cyl's should be retracted on the implement so there is no pressure or load.
You can make two dummy QD's or just one in most cases.
On the end of each dummy, add a small length of PVC tubing that will screw in the threads and stuff it with cotton or rags and add a PVC cap with a small hole in the end.
Any fluid weeping from the hoses will be caught with the dummy QD's.
The tractor side does not usually cause ony problems.