Insight - Desperate for taxes, Puerto Rico tries to get grip on underground economy

Mattress repairman and fruit vendor Angelo Lopez holds a coconut and a sugar-apple in the shed which he calls his factory in Lares, western Puerto Rico April 7, 2014. REUTERS/Ana Martinez

LARES, Puerto Rico (Reuters) - Mattress maker Angel Lopez is both a problem and an opportunity for the Puerto Rican government.

His one-man business works off the books as part of a vast underground economy, which doesn't directly pay into the treasury's coffers and is a major headache for an impoverished island that is $70 billion (42 billion pounds) in debt.