I have done a scientific project as a part of my graduation program and now i want to present my work through presentation slides.

Query: There were some techniques which didn't work and i had to another techniques. So, i want to name those techniques on a single slide but i am unable to find a suitable title for that slide. I don'think that i should use "Challenges" as title because i think that it would be suitable for those techniques which pose some problem to me but i managed to solve them somehow.

So, what should be the title of my slide on which i want to write the techniques that failed?