"Bobby Conkers"...... Awesome Name......and even better Avatar,(The Baddie/Goodie from Blake 7 i believe?!!)
Main thing to remember with the mains powered "Dremel" type machine,is that the varying speed settings can be seriously fast,hence Burning/melting of plastic can be a result!
I always prefer the meticulous,(and SLOW
!!),patient,use of hand files and scalpel blades!
HOWEVER,when needs must,i have,and use the "Parkside " battery operated tool,just as good as the Dremel,(IMHO),a LOT cheaper,and battery operated,hence,(With the lower voltage),much more user friendly and less destructive!!
Hope that helps,
Andy