@Simpleton
It is a song by Sentenced and a corruption of the saying "Aika kultaa muistot" lit. time coats memories with gold.
Also "aikaa multaa muistot" is nonsense, since "aikaa" is a conjugated form of "aika" - ie. "näin kulutan aikaa" "this is how I spend time" - and just the plain form "aika" stands for both "time" and "time to".
"Aika multaa muistot" would mean in this case either indeed " time rots memories" or "time muddles memories", though amusingly both can be translated as "time to coat memories with gold" for the original saying and "time to decompose/rot/muddle memories".
All that aside, it is just another metal reference, of which the author is apparently a huge fan of.