two aspects:
1) solid compounds show extremely broad spectra (this can be overcome by magic angle spinning). so if you have solid and liquid samples together, all you would see from the solid might be some "baseline noise". obviously this depends on the relative amounts in the sample.
2) solid particles in a solution can lead to huge field inhomogeneities, ("bulk susceptibility") leading to broad lines (also of the liquid part). -> you should filter it if possible.