How to remove dowelled spindles
The spindles may be fitted to the stair tread by use of a dowel. These will normally be glued into place.
Using a fine toothed handsaw, cut out a small section of spindle about 100mm (4”) above the tread. You may need to use a jab saw, or coping Saw with the blade set at an angle, for access to the first spindle.
Grip the spindle with a pipe wrench or adjustable spanner and with an upward twist, break the bond, freeing the spindle from the tread.
Once all spindles have been removed, clean out the holes ready for re-use with the new spindles if required.