This is one of those endeavors that usually winds up being much more than meets the eye. If these are old folders, with the scales pinned/riveted on, it's not an easy thing to do. Generally whats involved is that you must break the folder down, meaning that you have to remove ALL the pins that hold the folder together, just to get at, and remove the old scale pins.
Essentially you take the whole folder apart, and in most cases you wind up destroying bolsters, and possibly one or two linders during the tear down.
I've had a number of people bring old slipjoints to my shop, asking me to replace handle scales....and then they freak out when they hear the cost. In my opinion it's less time, effort, and shear frustration to completely build a new slipjoint from scratch...and it generally winds up costing the customer about the same amount of money as replacing broken/damaged scales on this type of knife.
Not saying it can't be done, but it is a great deal of work....generally much more than most folks realize or imagine.
