"Sculpture is very dirty but I like to get clay on my hands," artist Elizabeth Catlett said to the Howard University sculpture students standing around her yesterday concentrating more on their tape recorders, cameras and notebooks than this rare lesson.

A paint-smeared denim apron tied around her waist, her black pumps exchanged for red slippers, and her black cat eyed-shaped glasses sliding unglamorously down her nose, Catlett looked like a grandmother over a batch of biscuits, not a famous artist.

Then Catlett bent her wide girth toward a garbage can, pulled out the dry plaster, mixed it, and emerged ghostly white up to her elbow, her only jewelry, a gold wedding band on her third finger, completely hidden. "You can't be afraid to do anything," she said, smiling. "You've got to learn how to lift. Girls, don't look for someone to help you. Now I have lots of muscle," and she shoots her arm into the sky, a wide streak of flesh, "but it didn't start out that way. Look!"

Elizabeth Catlett Mora is a woman of two worlds. Only two generations removed from salvery, the Washington-born Catlett has lived in Mexico for the last 30 years but her art owes as much, and returns as much, to the Afro-American experience as the Mexican art trends.

"I am inspired by two people," she established quickly, her smoky cabaret singer's voice alternating between English and Spanish, as she tells how her views have been shaped by racism, sexism, political oppression, strong family ties and artistic obscurity.

As she nears 60, Catlett, who has long been regarded as one of the world's fine artists by art scholars, is enjoying a lively renaissance. Though she has remained active in Mexican art circles, her name became one associated with the past to most Americans. But after a major retrospective of her work in Mexico City in 1970 and an article in Ebony magazine the same year, Catlett was rediscovered by a younger generation of blac artists, becoming a mother figure for many of them.

This week Catlett has been conducting workships in sculpture and print-making at Howard where, earlier in the week, she was honored at the university's annual Charter Day dinner. Tonight at 7 o'clock Catlett and her husband, the artist Francisco Mora, will lecture on Mexican art at Howard's Fine Arts Department.

"Part of my acceptance in the art world now is because of my maturity," says Caltet. "In the '30s and '40s tokenism was practiced by the exhibitors and only Jacob Lawrence or Horace Pippin would have a show. Now the art world is slightly more broad minded. It's both a response to the political demands to the '60s and the economic realities. Black art is marketable."

In the last six years Catlett has had a number of exhibitions in black galleries, notably Howard, the studio Museum in New York and the National Center of Afro-American Artists in Dorchester, Mass. She was commissioned to do a bust of Phillis Wheatley, (the 18th-century poet, who was the first black to have a book published in the United States,) for jackson (Miss.) State University, and is currently working on a major piece for Howard's School of Engineering. her 11-foot statue of Louis Armstrong, the jazz trumpeter, was unveiled in New Orleans last Fourth of July before millions of television viewers.

Except for the realistic pieces, like Armstrong, her sculpture follows the traditional African form but also show the classical training she has received from Grant Wood, the carpenter and painter; Ossip Zadkin, the refugee French sculptor; Francisco Zuniga, and Jose Ruiz. Her graphics, especially her use of bright, mosaic colors, and her sense of space, have been inspired by Hispanic artists, such as muralist Diego Rivera, an early influence.

Figures of women surface repeatedly in her work. She has a firm sense of feminism and was very close to her mother, the late Mary Catlett, who was a truant officer in the District schools. Catlett's father, a teacher, died before she was born, leaving her mother with three children. Having to live frugally, receiving her education on scholarships, has been only one of the forces in her life.

Her strong-willed and blunt manner has been drawn from any number of battles. "It's too bad she's a Negro, isn't it," said a teacher at the Carnegie Institute of Technology, causing Catlett to transfer to Howard. She has had to battle her own laziness, and tells, very frankly that she was fired by the Works Progress Administration because she spent her salary instead of doing the mural assigned. "It was a great influence," shesays of the job that never really was. "I learned you can't play around."