O6-benzylguanine and Carmustine in Treating Patients With Unresectable Locally Recurrent or Metastatic Melanoma

DISEASE CHARACTERISTICS: * Histologically proven unresectable locally recurrent or metastatic melanoma * Chemotherapy naive with no more than 2 prior immunotherapy regimens (including cytokines, vaccines, or adjuvant interferon) OR * Prior chemotherapy failure with no more than 2 prior immunotherapy regimens (including adjuvant interferon) and no more than 1 prior chemotherapy regimen (which may include carmustine) not including antiangiogenesis therapy * Measurable disease * At least 20 mm in at least 1 dimension by conventional technique OR at least 10 mm in at least 1 dimension by spiral CT scan * No disease confined only to the CNS * No uncontrolled symptomatic brain metastases regardless of other disease sites PATIENT CHARACTERISTICS: Age: * 18 and over Performance status: * ECOG 0-2 Life expectancy: * At least 12 weeks Hematopoietic: * WBC at least 3,000/mm\^3 * Absolute neutrophil count at least 1,200/mm\^3 * Platelet count at least 100,000/mm\^3 Hepatic: * Bilirubin no greater than 1.5 mg/dL * AST and/or ALT no greater than 3 times upper limit of normal * PT normal Renal: * Creatinine no greater than 1.5 mg/dL OR * Creatinine clearance greater than 60 mL/min Pulmonary: * DLCO at least 70% predicted Other: * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No concurrent significant psychiatric or medical illness, including active infections, that would interfere with study therapy or increase risk * No other malignancy within the past 5 years except curatively treated nonmelanomatous skin cancer, carcinoma in situ of the cervix, or superficial bladder cancer PRIOR CONCURRENT THERAPY: Chemotherapy: * At least 4 weeks since prior systemic chemotherapy (at least 6 weeks since prior carmustine or mitomycin) and recovered * No other concurrent chemotherapy or investigational antineoplastic drugs Radiotherapy: * At least 2 weeks since prior radiotherapy and recovered * No concurrent radiotherapy Surgery: * At least 3 weeks since prior major surgery and recovered Other: * At least 4 weeks since other prior anticancer systemic therapy and recovered