Mac OS has very mature mechanisms to optimise its RAM usage as part of the Virtual Memory system; memory compression in Mavericks and later has improved on that. Don't be fooled by all the RAM apparently being in use as the 'File Cache' is just the system opportunistically using spare RAM to buffer data that it might need again: the system will dump it just as soon as it has a better use for the RAM.
What we can be certain of is that loading another program (Memory Clean) will consume both RAM and CPU cycles and be a possible source of extra bugs - not a good start ;-) Quitting applications remains the best way of freeing RAM.
Even before Mavericks, the OS was pretty good at managing itself, but eventually the best thing is to quit your unused apps or if that's not possible, buy more memory.
John Surtees 