Deleting Items

[(XBOX)MajorJohnson92]

I've recently started to build extra weapons and warframes to get more MR. I want to delete the extras to make more space but I can't see which were my originals with potatoes, forma, and lenses, is there something i'm missing?

[Zefat]

You wont get mr from already mastered weapons/frame/archwings/pets/sentinels/sentinel weapons. If the issue the exact same item and both are maxed and you want to delete the un-potatoed, un-formaed one its difficult, if you have a skin equiped on a warframe you can see the difference, if you forma the one you want to delete and you are able to distinguish your formaed+potatoed weapons from the now unranked trash x'D
 

Hope this helps, 

[SurrealEdge]

You need to clarify what you mean by building more weapons, weapons you've already mastered won't grant you more affinity, only new weapons you haven't used yet will go towards that.

As for identifying what has what, there's no way to tell currently, aside from seeing what rank each weapon is.