AirPods Pro Silicone Ear Tips Turning Yellowish

I have noticed that the silicone ear tips of my AirPods had acquired a yellowish tint. This might sound disgusting but I’m not sure if it is earwax because I always clean my ears, and my AirPods including the tips with a cloth. Perhaps it may be because it is silicone?

So can anyone tell me how to restore them to a pure white color again?