Method I. Fill screen with an inert solid, clne or any other such thing. Pause and use the prop tool, set it to "type" and put in the value to get your element you want to place. You can list elements below in the comments.
I've found very little so far.
Spng - 90
Rime - 91
Etrd - 50... and it goes on and on.
Method II. Cheat engine, others have explained this better than I could. Look for it.
Method III. *Laziest* Use reactions to get elements. Such as PLSM being made from Fire + Heat. Or such.
Method IV: Use lua and basically duplicate the elements, they wont be locked as far as I know.
Method V: Actually use new lua modded elements. Neither are those locked.
Edit: Funny enough. LIFE is locked but the actual life elements arent.
...Or you can use the freecoins code and just buy them all, like intended, but thats silly!
You can edit "Client.h" in the source code with this code and get 999999999 coins:
Ok, You won... But I still have 999999999 powdercoins.