A good but expensive stripper.
Alternative:
Remove the architrave, door stop and stair rails if you have them. Get the lot profesionally dipped. or replace all, either would be cheaper than stripper. Or even take them out side and burn it off but carefull not to scorch the timber.
Obviously the remaining would have to be stripped on site.
Stair rails under bannisters are normally held in place by the uniformed spacers. If you want to retain all rails carefully cut the first rail cutting a 45deg cut to enable the rail to be removed from the remaining cut section,
work it loose from the spacers. Prise out the first four spacers and the cut piece of rail put that with the cut rail if replacing and glue back the cut portion. Work out the next rail tap out spacers and so on for all other rails, no need to cut furthr rails.
Alternative to dipping or replacing is to take the removed timber outside and burn it off being carefull not to scorch the timber.
Best of luck. Done it, been there time consuming but worth it.
bob, January 2011