Can I sell items that may or may not contain copyrighted material?

I use photo editing software to create photo collages and some may or may not contain lyrics to copyrighted songs. I do this for personal use usually to give to my mother for her birthday and mother''s day. We were thinking of starting a business doing this: creating photo collages for people and they may contain song lyrics, sayings, poems whatever that person wants as long as it is not derogatory or anything like that. I couldn''t possibly predict what the customer might potentially want besides their photos on the photo collage, so if I created the item and sold it to them, could I get sued for doing this? I know I potentially can, but would I actually legally have to get permission for every copyrighted saying, song lyric, or poem that a customer would want before I could legally create and sell it to them? I could do it without the lyrics and stuff, but it just makes it more meaningful to me.