First, put some hot water in the keg and pressurize. Run the water into a glass and check for soda smell. If it's bad, clean and try hot water again. You might have to replace the o-rings inside the plugs, if the smell is too bad.
You really only need about 5 psi to check the seals and purge the tank.
And if you take the plugs off, be really careful not to mix up the in & out. I do all of the in plugs and replace them, then take off the out plugs.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
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