This is the first step in containing the containment. Start by putting on your hazmat suit, because things are about to get messy.
Step 1: Contain the containable object in a clear plastic bag. Make sure the bag is at least 6mil thick and has a gusseted bottom for extra containment security.
Next steps: Sub-Procedure Beta (for when things get really messy), Sub-Procedure Gamma (for when you need to contain something that's also radioactive), Sub-Procedure Delta (for when you need to contain something that's also sentient).