As soon as the rose seeds have been removed from the rose hips, rinse the seeds in a solution of purified water (any bottled water will do) with 5% bleach. This would be about two teaspoons of bleach per cup of water. Rinse the rose seeds with plain bottled water in a strainer, then soak the seeds in straight 3% peroxide for 24 hours. CAUTION: Do not mix bleach with peroxide because there could be a chemical reaction.
Growing roses from seed can be challenging, since the majority of seeds you collect often won't germinate regardless of your efforts. Fortunately, most rose plants produce a large quantity of seeds inside their rose hips, so it usually isn't necessary to achieve a high success rate. Keep in mind that the plants that grow may be different in appearance or other characteristics from the mother plant, especially if that plant is a hybrid of two varieties grafted together.
Black Spot: Rose plant leaves with black spots that eventually turn yellow have black spot. This is often caused by water splashing on leaves, especially in rainy weather. Leaves may require a protective fungicide coating, which would start in the summer before leaf spots started until first frost. Thoroughly clean up debris in the fall, and prune out all diseased canes.