yikes... that looks like some detergent or vinyl install solution (soap)
leftover stains.
stripes should be solid black.
i suppose you can try a mild polish (ScratchX) to see if you can get a
slight layer off the top... and make sure to wax afterwards.
similar issue at the tint shops. they install tint but dont do a complete
wipe down on the window sills and seats/cargo area on the inside so
a lot of times left with soap solution stains.
