Melanoma is a life-threatening cancer which poses a significant health burden, especially when metastatic or spreading to areas other than the original tumor growth. Although various treatment options are currently available for melanoma, melanomas that have metastasized widely to the skin pose a significant clinical challenge as the available therapies have limited effect. This study proposes the use of a topically applied compound named diphenylcyclopropenone (DPCP) which has been shown to be effective in treating melanoma patients whose diseases have spread widely throughout the skin. DPCP works by having a patient's own immune system, which is usually used to fight infections, attack cancerous cells. This compound has commonly been used to treat other conditions such as warts and hair loss throughout the world for many years and is known to cause limited side effects. Altering a patient's own immune system through topical treatments has also been shown to benefit patients with other cancers that have metastasized to skin such as breast cancer. In this study, the investigators will use DPCP to treat cutaneous metastases of various cancers including melanoma. Our overall intention is to get a better understanding of effective immune responses in the skin that may mediate metastatic cancer regression or cure.