victorian lintel

[RK]

Hi, I would like to paint a victorian lintel.

Currently, the surface is uneven and the paint is flaking.

Firstly, how do I remove the old paint, it could be lead based. Scraping it off does not seem to work, will a hot air gun work on masonry?

Secondly, how do I prepare the surface for the new paint?

Many Thanks in advance.