I use Tung oil, you can soak the trivet in or brush it on and I take the excess off with air blower. Let dry overnite, used sanding mop lightly, apply another coat, again let dry overnight and if not satisfy repeat one more time.
Now another way if you want a shinier finish don,t buff after the first coat just reapply after it is dry, just buff after the 3rd coats,
Hope this help