donny wright

Can anyone advice on the use of crushed oyster shell with clay and sand all mixed to form a flux. This is an evidence driven question from an Iron Age metal working site where we have crushed oyster shell down 10mm x 5mm down to dust, tiny oxidised and reduced clay pieces, with small pieces of magnetic smithing slag and hammer scale and tiny magnetic metal flakes, all within the clay and sand silts of a small prehistoric pool.