These whitish specks are possibly hot water heater dip tube pieces. Many 1980s hot water heaters had a defective dip tube that disintegrates with time. The dip tube transports cold water from the hot water heater's top to the bottom for heating. Over time, the dip tube breaks down and white particles enter domestic pipes. If large enough, particles become stuck in sink faucet or showerhead strainers. If they're from the dip tube, these particles won't be in the toilet bowls, tanks, or automatic ice maker because they only affect hot water. Call your hot water heater manufacturer for help with this issue.