As your mentor, I want samples of your work. You're a skilled engineer; there is no question of this, <name>. What I hope to do though is analyze them for ways to emphasize goblin-oriented techniques in your future efforts. I need the following: twenty big iron bombs, twenty sticks of solid dynamite, and five explosive sheep - and keep the safeties armed!
Once I receive your crafted engineering items for my review, I will hand you a genuine Goblin Engineer Membership Card! So long as the card is valid, you will have unlimited access to any goblin engineer trainer anywhere in the world.
This card has its dues paid for in advance for fourteen days; all cards expire after two weeks of activity. When it does, pay your next set of dues to any goblin engineer trainer in order to get another card; without the card, your membership will temporarily lapse and you cannot access new schemata.
This never affects what you already know; once a goblin engineer, always a goblin engineer.