This is very strange. This morning I've tried cotton pads (not balls, because for some reason we don't have any, so I took the pad apart and frayed it), dipped it in vaseline and used the firesteel. It didn't light. Then I tried the dry grass. It didn't light.
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You only need a little bit of vaseline. Your shavings look to be good. You just need more of them.
Try scraping your steel all the way around, so it wears evenly.
Sometimes I use the spine of my knife at 90 degrees against a stick, pushing down and scraping some fine sawdust like curls off. Try using a thinner striker. Like a stanley knife blade, or a broken junior hacksaw blade, and hold the steel steady, with the tip right next to your tinder, and push down the striker just a little bit. Just in the middle of the steel. Dont come off the end of the steel with the striker. This will give you greater control, and better aim, and fewer sparks.