Carpentry and Woodworking - spots on refinished surface

I recently stripped our coffee table and resanded all the surfaces. I stained the table and noticed about half a dozen darker spots formed about the size of a penny or quarter. It lookes like stains from drops of liquid. I don't understand where the spots came from since the surface was thoroughly sanded down to raw wood.

I am dissappointed because everything else looks great. This only happened on the main large surface of course. The wings, legs, and bottom surfaces have no flaws; only the part that will always be showing. Does anyone have any ideas as to what may have caused this to happen (the table was finished and sealed before, but the surface was rather "gummy")? Is there anything I can do to correct it?

thanks

You may have to strip it againt to remove the spots.

When ready to stain and finish a stripped piece. Wipe it down with a cloth dampened in mineral spirits. Anything left on the surface will show up as an irregularity, generally a shine, where the mineral spirits hits it. Then you can redouble your efforts to remove it. This way you know it is there before you start to stain and find it that way. Mineral spirits won't damage the wood and leaves no residue when it evaporates.

Hope this helps.