Inclusion Criteria:

- Patients must have squamous cell carcinoma of the skin; patients with "unknown
primary lesions" at the time of diagnosis, if metastatic disease present with a
history of plausible primary skin site removed in the past, are eligible; for
example, patients with squamous cell carcinoma in neck or parotid lymph nodes with no
identifiable mucosal primary but with a history of the removal of one or more early
stage squamous cell carcinomas of the skin in an anatomically relevant lymphatic
drainage region would be eligible

- Patients must have measurable disease, defined as at least one lesion that can be
accurately measured in at least one dimension >= 10 mm with computed tomography (CT)
scan, magnetic resonance imaging (MRI), or calipers by clinical exam

- There is no limitation to prior treatments with local, regional, topical or systemic
agents except for prior systemic treatment with 5- fluorouracil or prodrugs thereof;
prior topical treatment with 5- fluorouracil is permitted; there is no restriction on
timing of last treatments as long as patients have recovered from expected toxicities
of greater than grade 1 and at least 5 half-lives of the last systemically
administered agent have passed

- Eastern Cooperative Oncology Group (ECOG) performance status =< 2 (Karnofsky >= 60%)

- Life expectancy of greater than 3 months

- Absolute neutrophil count >= 1,000/mcL

- Platelets >= 100,000/mcL

- Total bilirubin within normal institutional limits or up to 2 x upper limit of normal
(ULN) if patient has Gilbert's syndrome (elevated unconjugated bilirubin from
decreased UDP glucuronosyltransferase 1 family, polypeptide A1 [UGT1A1] activity)

- Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase
[SGOT])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT])
=< 2.5 X institutional upper limit of normal or up to 5 X ULN if known to be caused
by liver metastases

- Creatinine less than 1.3 mg/dL OR creatinine clearance >= 30 mL/min/1.73 m^2 for
patients with creatinine levels above institutional normal; note creatinine
clearances between 30 and 49 mg/dL necessitate dose modification

- Patients must not be candidates for curative locoregional treatments; patients with
recurrent locoregional disease following surgery and/ or radiation for which a
resection is unacceptably morbid and unlikely to be curative are eligible

- Multi gated acquisition scan (MUGA)/echocardiogram must show ejection fraction (EF)
>= 50% for patients with a history of coronary artery disease (CAD)/myocardial
infarction (MI)/congestive heart failure (CHF) or as clinically indicated (principal
investigator [PI] discretion)

Exclusion Criteria:

- Patients who are receiving any other investigational agents or anti-cancer treatments

- History of allergic reactions attributed to compounds of similar chemical or biologic
composition to capecitabine

- While not excluded, patients taking Coumadin-derivative anticoagulants (warfarin) or
phenytoin must have international normalized ratio (INR) or drug levels monitored
frequently

- Uncontrolled concurrent illness including, but not limited to, ongoing or active
infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
arrhythmia, or psychiatric illness/social situations that would limit compliance with
study requirements

- Pregnant and lactating women are not eligible for this study

- Prior treatment with systemic capecitabine or fluorouracil (5-FU) therapy