Tiptops are the most prone to this type of wear but the snake guides may also be affected. If the tiptop requires replacement many tackle shops that sell fly rod tiptops should be able to remove the worn one and replace it with a new one for you. Worn guides are more complicated to replace and consulting with your local fly shop or a custom rod builder is strongly suggested. Check the ferrules for any grit or cracks. To clean them simply wipe them down with a damp cloth.
Repair is difficult at best and often impossible.
If you simply cannot part with that rod check with a reputable rod builder or your local fly shop for advise. Unfortunately ferrule damage is usually terminal. When checking the reel seat make sure the glue bonding the components together is still reliable. If the reel seat is of the screw locking type ensure the grooves are clean and do not bind the nut when worked. A miracle of modern technology, new fly lines not only have a long lasting but also durable PVC coating that has benefited all fly fishers in becoming better fly casters.