This article (from the ‘Portugal News’  16th October 2014 (small world!)) explains where Dulcie’s bottle tops go to.

Crime prosecution service worker Sue Botwright, who lives in Sutton, London (UK), regularly travels to the Algarve and brings with her thousands of bottle tops collected by herself, colleagues and friends in the UK, to help beneficiaries of Portuguese charities.

Sutton CPS worker spearheading mass bottle-top collection for Algarve’s needy
In Portugal bottle tops are often collected and sold off in large quantities for recycling, with the proceeds going towards various charities.
Among the most common causes are the purchasing of prosthetic limbs for child amputees and wheelchairs for the disabled.
Briton Sue Botwright has been visiting the Algarve since she was a child, mostly with her mother who sadly passed away a year ago.
Sue, who lives in Sutton and works for the CPS (Crime Prosecution Service) travels to the Algarve at least twice a year and has a particularly close relationship with Albufeira and its residents.
She therefore wanted to give back something to the city and collecting the bottle tops to help those less fortunate seemed to be the best idea.
She has to date been solely responsible for collecting thousands of bottle tops, encouraging her friends and work colleagues to follow suit.
Among acquaintances helping collect the bottle tops are workers at Kent National Health Service, colleagues and friends at Societe General Bank, and also members of Stoneleigh Methodist Church. Not to mention Sue herself and all her friends and colleagues at the Crime Prosecution Services in England.
It is then Sue who solely bears the cost of posting the packages more than 1,700 kilometres to a friend in Albufeira, from where they are taken to the Portas da Vila bar (well-known locally as the ‘House of Shells’) before being collected by members of the local Santa Casa da Misericodia charity and the local Fire Brigade department.
Albufeira resident and friend Elisabetta Sestito says: “We the local residents of Albufeira would like to express our acknowledgement and appreciation for the good job that Sue does and all the others who contribute to this worthy cause.”