The liner of most decent boots can be heat moulded when they are new which helps speed up the bedding in process. Basically it makes them more comfy from the start and saves you about 5 days worth if bedding the boot in by just skiing in it. However if a boot is second ham it will do nothing. The liners will already be bedded in so heat moulding will not do anything. Always be carfull buying second hand boots as liners have a fairly short life span. A traditional liner will give you around 150 days use and an intuition maybe only 100 so if the boots have been used quite a bit there may not be much life left in te liner.