I use Snow Seal on my straps only because I have it for the leather on my Bean boots and Sorels. Brillo pad and some wd40 on the rivets, just an idea, and I would spray the WD on a paper towel and rub it on, not a direct spray onto the bag.
I have a clean beaver stick hanging horizontal from the ceiling in my shop and I drape the bags over that, with the straps hanging un-buckled to prevent cracks or curves where the strap runs through the buckle. Keeps the mice out and bags in a safe spot.
Now for the most important items, you'll need a rocking chair, a wood stove, maybe a dog at your feet, a small lamp and table and something to take the chill off in a glass. and that's where Duluth Packs shine. You can work that leather soft some cold winter night while dreaming about trips past, works every time.