I love my Ergo carrier (I bought it when Laddie was born, and have used it with him and Scout), but I do not love my babies' proclivity to chew on the shoulder straps. This is not a unique problem, as even a brief search for "Ergo teething/drool pads" will show! Tired of either washing my carrier too often (not good for longevity) or having dried slobber (or even spit up... yuck) all over the straps, I decided to make a pair of my own.
I traced the outline of the strap onto some paper, added some seam allowance, and got to work. Using some scraps of Scout's crib sheet/changing pad cover fabric, plus an unused terry washcloth as the backing, I stitched up a quick set of strap protectors.
These were so simple that I'm wondering why I didn't try this sooner! There are some free patterns available should you need one, but I was happier with my self-drafted version. Now when they got soiled, it's a simple matter of unsnapping the pads and throwing them in the wash.
Sometimes, easy does it best!