Pierce each potato in several locations to vent steam while baking and prevent explosions. Dissolve 2 T salt in 1/2 C water, then toss potatoes in the mixture to coat the skins. Do not moisten with oil.
Roast the potatoes at 450 until the center of the largest potato has reached 205 degrees, 45 to 60 minutes. Don't guess, use a thermometer.
Remove from the oven, brush with oil, then return to the oven for 10 more minutes.
Remove from the oven and immediately open the potatoes to release the steam.