Usually you'd put about 2 drops... maybe 3 (and they do mean "drops"... not squirts) on the sensor swab and wipe across one time. If you're using the "Eclipse" solution, it's nearly pure methanol and will evaporate VERY quickly leaving virtually nothing behind (the fluid doesn't leave a residue -- that's the whole point of it.)
This looks like you used a fluid that left a residue and dried to muddy spots.