I came up with the idea of being able to right click an empty bucket on cobblestone/obisdian created by lava which would put water or lava in your bucket and make the block dissapear. I personally think this is a decent suggestion as it's extremely frustrating if you get trapped by someone or just accidently trap yourself by placing lava and turning it into obbsidian/cobblestone.
Example: Me and a teammate go up a ladder in a little house to kill another player. I put lava down to set him on fire and my teammate puts water down, whilst doing so this causes the ladder to be trapped as the lava turns into cobblestone/obsidian. So if this got added I would be able to right click the cobblestone/obsidian with my empty bucket and it would dissapear and give me a water bucket or lava bucket.
@Tacosbefriends