We just moved into a new (to us) home. The washer/dryer are amazing - HE, new-ish, really "advanced". <- our last one was 10 years old and so basic.

Soooo, with this amazing new washer, I'm surprised that if we leave clothes in it for even 6 hours, they smell like mildew. Of course I've experienced this in the past, but it was always after forgetting the laundry for 24-48 hours.

Could there be grime from the last people that lived here? Is there a solution I can put through the machine to refresh it a bit?

ETA: It's a top-loader