The plastic sticker razor is perfect for removing stickers from cubes. The plastic material is durable but won't damage your cube. It features one dull side for holding the blade comfortably with your fingers, and one sharp side for removing stickers.
Some tips for maximizing the life of the blade:
Only use the blade to pick up one corner of the sticker. You can use your fingers to pick up the rest of the sticker.
Try turning the blade around if one side is getting dull
You can use a diamond file (sold in Accessories section) to sharpen the blade if it gets dull. Just gently file off the rough spot to make it sharp again, and it should work just like new.