I’ve been trying but she always runs away. :(
I just realized that if I catch her and cage her, how do I clean the cage?
The only thing that would help that situation you describe wouldn’t be figuring out how to “clean her cage”. You would have to put her in a large enclosed area that could contain food, water and a kitty “toilet”. That would take care of the momma but when the kitties were born, what then, in terms of tiny babies and “toilet” needs.
I agree with the advice to try to provide an area where she could have the kittens if she chooses, but where she is free to come and go and you would not feel you had to keep cleaning up the area.
As for her running away, obviously she fears being trapped or whatever “for her own good”. Keeping on trying to get her just feeds that sense of defensiveness.
All I can add is try to get her comfortable with you as a friend who only wants to give her sustenance and a few kind words, so she would be content near you, in your area. Might try calling her a particular name over and over in a gentle tone.
I once sang a song to such a cat as that, tho she wasn’t old enough quite yet to be pregnant but she needed my help and was pretty wild. Today that cat has been with me about a dozen years...she came around.
P.S.
Need to mention, the cat I just told you about in my other post, IS BLACK!