If your fireplace surround has a black finish metal frame it will need retouching, re-blacking or re-painting about once a year.

Preparing the surface

A - Painted surface

If your fireplace was previously painted with an oil-based paint you need to first remove the paint .
If heat resistant paint was used and you wish to re-paint it than advance to B.

This can be done using paint stripper. Make sure the paint in the relief of the surround has been removed. Ensure that you wear sufficient protective clothing and that there is adequate ventilation – refer to the paint stripper’s manufacturer’s guidelines.

Please be aware that the metal surface of the fireplace surround, once stripped, will be prone to rusting.
It would be best to cover the prepared surface with your chosen finish as quickly as possible, to avoid too much rust forming.

Alternatively, you might want to remove the whole fireplace surround and have it sandblasted to remove the paint.
Please be aware that this will strip the surface totally, leaving it very prone to rusting.

B - Preparing polished, blacked or heat resistant painted surfaces

Remove loose rust, paint and dust with either a wire-brush attached to an angle-grinder, or a hand wire-brush.
You can also use steel wire-wool, but not sand paper.
Remove the main bits of rust, working well into the grooves as well.
There is no need to remove every bit of rust.

Re-blacking of the fireplace-surround