You can skip the Spark of Ingenuity questline on alts and instantly receive 5 Sparks if you completed it on your main.
Once you collect 5 Spark of Ingenuity on your main, you can talk to Greyzik Cobblefinger at the Engine of Innovati on in Valdrakken on alts to skip the whole questline and receive 5 Bottled Essences and Essence Detector. The skip will only work for characters that haven’t started the questline yet.
