I know it from a David Lee Murphy song (love this voice and this song together). It's about not letting an appearance of age fool you about what's inside the person.
It's also about love that grows mellower, yet stronger, over time. Oh, yeah, "there might be a little dust on the bottle, but it's one of those things that gets sweeter with time."
And here she is, Mrs. There Might Be a Little DOTB. She's pretty sure that, just like the song, the dust on the bottle isn't going to fool the one most important to her. After all these years, she's pretty sure that a few gray hairs and a few more pounds are just dust on the bottle when you've been together this long. After all these years, she's pretty sure that a difference of opinion and an annoying habit or two won't obscure what's in her heart. After all these years, she's pretty sure that they'd both change their shortcomings if they could. . . but it's good to know that the heart doesn't mind a little dust on the bottle once in a while.