Used Metal Knife on Aluminum Cake Pan, is it Ruined? I'm learning to make cakes from scratch and bought two of these 4-inch round pans to make a small layered cake.

After letting my layers cool, I turned one layer out and the cake fell from the pan after a few good raps on the bottom. The other layer was being a bit stubborn so i used a butter knife to separate the cake from the edge of the pan.

After I did that, I noticed some small shiny bits of metal on the outside of the second layer. I have two questions:


Is this a normal consequence of using aluminum cake pans or did I
get a really low quality pan (it was the cheapest one at my local
kitchen store)? 
If this is a normal consequence of using aluminum
cake pans, have I ruined this pan by scratching it or can I use it
again as long as I don't use a metal knife to release the cake?
Steel (as used in knives) will always scratch aluminium, which is really quite a soft metal. Glass and even some plastics can mark it quite noticeably as can storing aluminium pans stacked together. In other words it happens. Don't worry about it. The pan doesn't look as nice but it's not ruined. The main reason to avoid scratching it is to avoid getting fragments in the food.

I have a set of miniature pudding basins made of aluminium and if things don't just fall out, the only tool I can find that helps is a butter knife (they're too curved for any of my silicone tools or plastic pallette knife to get in nicely). But an old, smooth, worn one, and that doesn't scrape material off (though it does leave a mark.)