DSPOBJD OBJ(&Lib/*ALL) OBJTYPE(*ALL) OUTPUT(*OUTFILE)
On the AS400, you need to look at last used date on the objects.
you can create and file of all objects in a library by using the DSPOBJD command. Here is a sample.
You can query this file, or send it out as a .csv so you cna use Excel to analyze it.
Look at the last used date and the creation date.If the last used date is blank and the creation date is not very recent, it is not used.