County councillor Carolyn Trowbridge, cabinet member for leisure, arranged the surprise visit as a treat and to say thank you for the hard work carried out by the students around Stafford Castle and the local area.
Tutor Melanie Edge, aged 45, said: "We are part of Futures@southstaff college at Penkridge and we started this social action project in September for our students with complex needs and will be continuing until the end of the academic year in July.
"It has been a very interesting project and initially the students carried out litter-picks around the castle.
"We soon had that area tidied up so we branched out to Stafford, Western Downs and Highfields.
"We have also teamed up with Stafford Litter Heroes and posted the weights of litter collected on their Facebook page.
"The five students, Luma, Nathan, Jamie, Caitlin and Max, have all enjoyed taking part and it has enabled them to gain work experience, as well as employability and social skills."
"The students have been helped by college support workers Amy Blount and Dan Smith."
Councillor Nixon, who is mayor of Stafford borough, said: "These remarkable students are amazing."
Councillor Trowbridge said the visit by the mayor and mayoress had made the day for the students.
She said: "I was delighted to be invited to meet the litter heroes and the team maintaining Stafford Castle's herb garden and surrounding area.
"The teaching lead, Melanie Edge, has obviously put so much energy and time into making the student's time invaluable for the community.
"Her love for the area and her job have shone through and the castle looks so much better thanks to her students.
"I would like to thank everyone who attended this special day and hope everyone will keep up the good work."