Children, especially toddlers, explore their environment through sensory play. It sounds like your daughter may be a hands-on learner. Lots of children begin to explore their diaper area and contents as they become more aware of the toilet learning process. Like several other moms have posted, some children are fascinated about what has come out of them. Some feel a sense of ownership, and don't want it to go into the potty because it disappears.
When it comes to children, there are 2 things you will NEVER be able to control and it is best avoid power struggles over them since they will always WIN. 1) eating 2) toileting. Keep in mind, the more you push, the more they push back.
A little gentle guidance and redirection will go along way. Offer more sensory experiences like playdough, shaving cream, goop (corn starch and water), corn meal etc... This is a great time to show her bathroom hygiene, like washing hands after diaper changes and using the bathroom. She will learn and eventually this will pass. Oh,the joys of parenthood! Best wishes!