Removal
If the clasp is being removed from a non-orthodontic appliance then it would be appropriate to claim an urgent Course of Treatment (CoT), unless an examination has also been provided in which case it would be part of a band 1 CoT.
If the clasps are being removed and the appliance was recently made, then this removal would be considered part of the original course and would therefore not generate a further patient charge.
Addition
If the clasp is being added to a non-orthodontic appliance then it would be band 4 (urgent) unless an examination has also been provided in which case it would be part of a band 2 CoT.
Repair or Replacement
If an existing denture has a clasp which is being replaced, it would be appropriate as a charge exempt item (free denture repair).
If the denture had only been provided recently, then a further claim wouldn't be considered appropriate as the alteration would be considered to be part of the original treatment.