From years spent around aircraft (recip/jet) and competitive shooting (rifle/pistol) I have permanent ringing in my ears. The early ear protectors are nowhere as effective as the ones now available. I have gotten used to the "noise" over time and use foam ear plugs whenever the situation requires noise abatement. You cannot undo the damage but can avoid adding to your hearing loss/acuity. I often wonder about the hearing loss experienced by those riding in cars with 400watt + stereos with booming woofers. Ride Safe