Do I need a different cloth for interior vs exterior?
Not really. Keep one clean side for exterior use and the other for interior to avoid contamination.
How should I wash it?
Machine wash on gentle cycle in cool water, no fabric softener, air dry flat.
Can I use it for plastic trim?
Yes, it’s gentle enough but have a separate cloth for best results.
How often to replace it?
When it starts to go fuzzy or build up residue you can’t wash out, it's time for a new one.