the small tools generally called a 'leaf and square' handy in real tight spots...
skimming a 2 inch gap is never easy..
the BEST way is to remove the architraves... skirting boards are a bit more tricky to get off in one peice if your not replacing them but architraves are easy...
you need to put it to the customer and price for it though...
remove with a chisel, score the back edge to avoid yanking plaster off (although your gonna skim it anyway)
this applies to nailed on archies btw...
tease em off al the way down, dont try and take the top off then the bottom, youll split em...
when theyre off (and this is the clever bit) use a pair of grips (dogs, moles, pliers, whatever) and pull the nails through the BACK of the architrave... this way you dont leave huge splinters in the front from tryin to knock em through....
leave the corners mitred (cos they'll be nailed together anyway, so youve taken all three sides at once geddit?)
stack em somewhere and remember (notate) which door they came off..
stick em back on with gripfill when youre done, the slight gap your left with you fill with acrylic decor filler (painters mate, whatever)
better job, easier to work on but price for it or it aint worth it...
if your gonna do the same with the skirtings.. good luck cos youve about a 50 percent chance of splitting the bloody lot, depends how well theyre fixed... usually a replacement job... and a job for a joiner unless your handy with a chopsaw and know a butt and scribe joint from a mitre joint Â