By receiving this quest from the donkey the donkey will give you 2 special crap metal. This special crap metal cannot be deleted or droped. Check your inventory and your storage boxes. Once you have found the special crap metal follow this steps:

1. Grep two special crap metal and put it into your backpack. You received this metal from the donkey on the begin of the quest.
2. Go to Krezvold (the blacksmith in town) and give the parts to him. 
3. Krezvold will craft the battle horseshoes for you if you give him 50 Silver coins.