Many manufacturers used foam surrounds to make speakers.Over many years this foam

will deteriorate and crumble to the touch or after music is played through them for only a few hours,even if the are brand new!

You will then have to have the speaker surrounds replaced which can get expensive and often cost more

than the speakers are worth.If rubber or treated cloth is used as a surround there should be no problem.

Best to ask the seller in advance if the surrounds are foam,they are best avoided altogether for harsh auto environments.