Comment by DiabloD3

Not only should you get rid of them, but also they are a fire hazard.

Also, do not accidentally plug surge protectors into each other, metal oxide varistors can star fires _without_ meaningful surge conditions when you do so.

I prefer to buy products without MOVs entirely due to the risk, with the exception of one, Tripp Lite Isobars; but I prefer to use series mode protectors such as Brickwall or SurgeX.