Training Question

Can someone tell me some tips for training dogs to pick up things in their mouths?  My dogs got some new toys from someone else so I got a toy basket to keep them in.  I want to train them how to “put away” the toys and “fetch” certain toys from the basket.  They both like to chew on these toys or play with them, but they won’t do anything with their mouths when they know I’m watching or have treats.  They do all these other behaviors to try to earn the treat.  I don’t know how to encourage them to bite/mouth the toys for treats.  If I hold a toy and try to put it in their mouths, they turn away like they think it’s bad to bite a toy and take it from me.  I’m not sure how to begin.