You know those disposable shower caps in hotel rooms that you always overlook? You might be surprised at what you can do with them when you travel.
Are you packing shoes in your suitcase that you don't want to get scuffed? Place each shoe in its own shower cap to protect its finish. Or, are you packing tennis shoes with sturdy soles? Put one shoe in its own cap and those rough soles won't scrape up against more delicate items.
Did you just polish your shoes before you started to pack your suitcase? Again, use a shower cap for each shoe and the recent polish won't end up on your clothes.
The next time you see them in your hotel bathroom, grab the shower caps and toss them in your suitcase. You can always save them for later.