I have a few old jackets that were water-proof/resistant in their prime.  Currently researching the best products to make them as functional as possible so I can avoid simply donating them away.

Products to Try

Sport Wash

Sport Wash Laundry Detergent

Gangers

… populate …

ReviveX

Gear Aid ReviveX Durable Water Repellent For Outerwear

Nikwax

… populate …

Tectron

Performance Polymer Water Proofer