First of all bit of history. During the 1960s it became a fashion trend to paint victorian cast iron fireplaces with another colour. So by the time you get round to restoring them you could well have 50 years of paint to remove! It is also best to start this project before you start decorating a room as the wall surrounding the fireplace will probably need repainting.
Caution: pre 1970s paint contained lead so it is extremely important to check out the health and safety guidelines.
Assuming that you will not be removing the fireplace from the wall, you should start by masking the surrounding wall with newspaper or masking tape. Also a plastic sheet should be laid on the floor to cover a large area. This is a messy job and you will be pleased you spent time on this stage.
Make sure you have the correct safety gear on. Start by applying the paint stripper with a paint brush. Cover the whole fireplace as the first layers of paint will remove quite easily. Leave the stripper to work for a few minutes , then with your wirebrush start brushing over the paint. Keep repeating this process using a pointed object like a small screw driver yo get into the fine detail. Be warned this process will take a few hours and the older the layer of paint the harder it will be to remove.
Once all the paint has been removed wipe down the fireplace with methylated spirit to remove any paint stripper residue. By now you should be able to see the fine detail that has been lost over time. Once you are happy that all paint has been removed it is time to restore the fireplace back to it’s former glory.
With an old paint brush cover the whole fireplace with a coating of cast iron paste. Make sure that you get into all the fine detail. Follow manufacturers instructions but usually it takes about 7 hours to work.
Once the paste has had time to work you should start to rub it off using a dry soft cloth. Take your time to rub all the dried paste off otherwise you will get black marks on your fingers everytime you touch it!
Remove all the masking and plastic sheets. Re decorate if necessary.