I successfully fixed some of the moth holes on things for which I had the original yarn or something close I could use. First I fixed the hole in my brown sweater. I thought it would be the easiest of the projects because it had the largest stitch size but I spent way too much time trying to do make the repair and at times made it worse. In the end it's ok. Basically I started by duplicate stitching over good areas and then created the stitches that were missing. A picture here wouldn't really show much since the sweater color was hard to photograph. I of course know the repair is there and it bothers me but there's a lot more that bothers me about the sweater. I need to redo the sleeve openings and shoulders and then I hope to wear the darn thing.
Next I fixed a hat. The hole was near the crown and I sort of matched the stitches and made it work. The repair isn't noticeable at all but that's more because of where the hole was.
These "tiger" socks I knit for my husband had a large hole. Because I had multiple rows to replace, I tried a different approach. I pulled out some of the damaged and also undamaged yarn until I had two good rows of stitches that I could put on needles, but I didn't cut or remove any of the yarn.
I didn't have the original yarn but I found some of similar weight in my stash. The hole was next to an area where the color pooled so it worked out to fix the hole in a similar color. I cut a long length of it and anchored the free end into the sock by weaving it in. Then with the stitches on the bottom needle, I knit a row. When I got to the end of the row I used a tapestry needle and wove the working end into and around some good stitches in the sock just beyond the edge of the hole. Then I purled back and wove the working end in. I continued in this way until I was one row from the stitches on the upper needle, ending with a purl row. I then used a kitchener stitch to join the two rows.
Here's how it looks. The stitches at the far right of the mending ended up a little loose (in the middle of the picture), so it's not "perfect", but it's a sock. I minimized the lumpiness the best I could - the hole was on the top of the ankle so it shouldn't cause any discomfort.
Here's the inside of the sock. I wove in all the broken ends of yarn. There were 7 rows of stitches that had to be replaced.
I still need to fix a scarf of mine. I knit it with two different yarns, one acrylic and one a wool/acrylic mix and curiously it was the acrylic yarn that was broken and not the wool mix yarn. I wonder now if the acrylic yarn just broke. It's a fun-fur type yarn so maybe it wasn't strong, and I did wear the scarf a lot. But just because moths weren't the cause doesn't mean good news because that fluffy yarn will be ridiculous to try to figure out what goes where. And there are 3 or 4 holes. Here's the scarf in happier times:
But there is more good news. I have gone through about 85% of my stash and have not found active moths and very little evidence of old moths. Whew! And revisiting my stash was good too. I have a lot of nice yarn!