Yes it is fine, keep a pair of scissors just for the tank...I use the little one for cutting your nails and they work fin and are small enough toget where I need to go.
Yep, some people use scissors, some people (like me, the cheap person) use their fingers, and some people even buy the little plant tweezers that you can get from foster and smith!
Edit: most metal that is used in cutting utensils is stainless steel... pretty much harmless. And it's not like you're leaving it in the tank for 20 years!!