You don't need to filter stuff if you know the filename! Just open the file with SimPE and click twice as shown:
Once you've "clicked here second," you just change the gender to 0x03 (unisex). For future reference, 0x01 is Female, 0x02 is male, 0x03 is unisex. I don't recommend doing this to anything but child and toddler clothes and maybe the OFB cook's outfit for elders.
To change the age, just click the line above the gender and change as follows:
0x01 Toddler
0x02 Child
0x04 Teen
0x40 Young Adult
0x08 Adult
0x10 Elder
You can also add them together, remembering that these are HEX numbers. YA/A is 0x48.
I was also able to make recolors of the men's NL bomber jacket that worked for Teen to Elder by setting the age to 0x5C. The women's jacket got a kind of "tucked in" effect on elder women, so that was only Teen/YA/A at 0x4C. I don't recommend doing this to anything that's not super bulky.