A safe first step is to re-wet the film and let the paper release gradually. Soak the negatives in room-temperature water with a small amount of dishwashing detergent for several hours, checking occasionally to see if the paper separates on its own. Do not force it off while dry.

Once the film releases, rinse it in running room-temperature water for about 10 minutes. Then use a brief final rinse with a wetting agent such as Photo-Flo (or equivalent) to help it dry cleanly, and hang the film to drip dry.

Key points: keep the water at room temperature, be patient, and avoid scraping or peeling the paper off dry, which could scratch or damage the emulsion.