To see oyster shells in your dreams, denotes that you will be frustrated in your attempt to secure the fortune of another.
Dream dictionary: Oyster Shells dream meanings
…Dreaming that you’re eating oysters indicates the impulses and sexual satisfaction. On the other hand, it means that you’re losing strength and your senses by pursuing pleasures and indulgences for yourself. Seeing a plate of oysters in a dream symbolizes beauty, humility, wealth and wisdom. Seeing oyster shells in a dream means that you’re frustrated on your temptation to secure your fortune and on how to spend money….
Dreaming of eating oysters suggests that the dreamer is losing the sense of morality due to engaging in activities that might be illegal. Dreaming of trading with oysters indicates that the dreamers unscrupulousness makes the dreamer search for illicit love affairs. Dreaming of only the oyster shells hints future failures and significant losses when trying to deprive others from things that belong to them.