Metropolis Mailbag [Blue Lettered Envelope]

Feature:
Metropolis Mailbag (English) [l]
Years:
?
Notes:
Logo from an issue of Superman (DC, 1987 series) released in 1991 - issue #78, but unsure when usage of this particular logo began/ended.

An icon of a ringed planet is used to dot the "I" in Metropolis in this logo.
Feature Logo: