I intend to use the hot air gun on an area of my staircase (the rest will suffice with a light sanding). I will then apply a paste of caustic soda and water, cover with soaked old newspaper and leave for 48 hours.
Now what could possibly go wrong?
Except that it's usual to cover the paste poultice with thin polythene. That stops the paste from drying out before it's done the job. Newspaper will dry out too quickly.