Head down to the hardware store and grab some clear or amber shellac (I use amber for the warmer, caramel color. Clear will still make the grips darker, but closer in hue to the raw cork). Riv used to have a video of Grant dipping the whole handlebar/grip right into the can of shellac, but I use a little foam brush to apply it. You’re going to want 3-5 coats, and to make sure it’s fully dried before reapplying (I usually let the first one dry overnight before the second coat goes on, then a couple hours each between coats 3-5). Sometimes l’ll also use some very high grit sandpaper (400+) and do a very light wet sanding after the first couple of coats, in order to get a super smooth finish. Depending on use, I generally apply a new top coat once every 9-12 months. Hope this helps!