Walter's Scrap Metal

 refers to an unmarked and repeatable quest in Fallout 3.

After the pipes in Megaton are fixed, Walter offers to buy Scrap Metal from you to maintain them.

Reward

 * Walter gives you 10 bottlecaps per Scrap Metal; if you decline payment, you will receive positive Karma (20).
 * You also get a 5 XP reward per Scrap Metal you give Walter.

Bugs
Walter is known to disappear, making the continuation of this quest impossible. See Walter for suggested fixes.