Prince Charles conducted Treorchy Comprehensive' s Combined Cadet Force's first ever inspection with wife Camilla
The Prince of Wales reminisced about his time cleaning boots as a cadet on a visit to a school, joking "I think I still bear the scars".
Charles was inspecting the Combined Cadet Force (CCF) at Treorchy Comprehensive School in his capacity as Colonel-in-Chief of the Welsh Guards.
The Rhondda Cynon Taf school's CCF, affiliated to the Welsh Guards, is one of six pilot schemes aimed at increasing recruits in state schools.
It also helps develop skills.
Speaking at the school, Prince Charles, who is on his summer tour of Wales with wife Camilla, said: "Today reminded me of my time in the cadet force when I was in school.
"I can understand something of what was involved, particularly cleaning boots and various other tack which kept us all very busy."
The prince conducted the cadets' first ever inspection together with the Duchess of Cornwall.
The CCF is a Ministry of Defence-sponsored youth organisation which provides opportunities in schools for young people to develop leadership skills.
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Treorchy CCF started last year and 80 pupils have now joined.
The prince told cadets they should be proud of the First Battalion The Welsh Guards serving out in Afghanistan.
"I think we owe the members of the First Battalion and all those who are fighting in Afghanistan our support and gratitude for the fact they're prepared to put up with such impossible conditions in order to achieve their objective," he said.
While at the school, the prince also announced a new Welsh youth initiative called Young Dragons, under which all of the uniformed youth organisations in Wales are joining forces.
Charles said the initiative was born out of a conversation he had with North Wales chief constable Richard Brunstrom on the royal train a year ago.
He said: "I must say it's taken me 25 years or more to get to this point. It always seemed to me an awful lot of wasted potential and human assets were also being wasted here.
Thank God it is still there and the smell is still the same
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"So many young people respond to this opportunity, particularly at that stage in life where so often it seems you need a bit of challenge and adventure."
He said he hoped more adult volunteers would be recruited as there were so many young people wanting to join organisations like the Scouts, Guides and St John Ambulance.
The Duchess of Cornwall later officially opened the new £10m South Wales Fire and Rescue Service headquarters in Llantrisant, Rhondda Cynon Taf, while Prince Charles officially opened the Ortho Clinical Diagnostics plant in Pencoed, Bridgend.
The factory, which is owned by Johnson and Johnson, employs about 350 people and produces immunodiagnostic tests to help detect diseases early before they progress and become more serious.
While at the plant, the prince praised the company's baby powder, saying he was brought up on it, as were his children.
"Thank God it is still there and the smell is still the same," he added
Later in the day, the prince joined up with his wife at the EcoDysgu holistic education centre in Tondu, Bridgend.
The centre was this year's winner of the Prince's Foundation for Integrated Health Awards for Wales.
The not-for-profit holistic education centre is set in 42 acres of the countryside and offers workshops and courses combined with complementary therapies.
Charles and Camilla were shown around the sensory garden and told about the reflexology treatment they offer.
Beth Ellis, a 21-year-old youth provision manager for Youth Bettws, said: "He was really approachable and really lovely. He was really interested in what we do here."