I pull the outer seal off the bearing and clean and add grease as appropriate, then replace the seal. It's easy. Usually, I preemptively add grease, as many BB bearings have minimal grease to begin with. The added grease helps exclude water and grit.
Most press-fit BBs are bad in that they tend to funnel water and grit right to the inner edge of the outer seal and then work it through the lip of the seal into the bearing as the crank turns.