PRT seals can usually be removed with fingers by pulling and twisting. If you use pliers, use great care not to damage the PRTs.

On 1980-and-earlier, the collars at the bottom of the PRT were movable and could be adjusted to increase the pressure on the PRT seal. Before replacing your seals, you could "re-seat" them by tapping on the PRT collars with the appropriate tool. After 1980, these collars were brazed in place and cannot be adjusted. If you tap on them to seat the seals, you're likely to unseat the upper end of the tube from the head, leading to a MAJOR PIA.

If you screw this up, or if you want to replace your PRTs anyway because they look like the ones above, see Snowbum's replacement instructions at http://bmwmotorcycletech.info/pushrodseals.htm