You want to cover them with aluminum. This is what you cover external wooden windows, external door frames. You get a box of aluminum= which is a 3 foot wide cool I think. There is different colors but white and almond are standard. You need with a called an aluminum brake. You measure the sides tops and bottom of the external wood parts ot the window.You cut a piece of coil the length of your tallest window edge. The you measure the side it will be an L or C shaped pice you need to cover the wood. You measure all the sides. YOu then mark on each end of you coli. Suppose you making a C shaped piece the side of the C are a half inch. the top is 2 inches. You put your coil in th ebrake clamp in and score it with a utility knife if your break has no cutter. Then you bend the break and it snaps your piece. Now you got a four inch piece to make you C. Put this piece i the brake and mark half an inch on each end of the coil. Pust the coil in the break to the mark meets where it bends. Lock the break then bend. Reapeat the other side. after you make this PM me and I can still how to instal the pieces, the cuts and snipps you will need. Good lucck!