Having pens and counterfeits on hand (I always keep around at least one spare of every consumable I can, just in case), going to one of the tinkering spots, and trying absolutely everything together to see what had results. Got some other good stuff this way (fairy dust in particular has several uses), but the high quality passes is by far the best use of these spots. Knew about Bearmarshal's Lin Lin solution too, and did that one the first time, but doing it yourself is far, far cheaper.