You may have partially dissolved debris or mold release compounds still clinging in places.
If the LP was used (you did not state) and damaged by previous owner, the noise you hear may have always been there but covered up by "cleaning" with a silicone cloth, record spray or other treatments.
I suggest Premier record cleaner for all used and new LP's. Premier is a new Dupont compound replacing (EPA banned) Freon. Anything on the record will be put into solution or removed completely by Premier and then a couple of washes afterward should make the LP not only quieter than before, but better sounding as well.
Exception listed above, that LP is damaged in which case only a new record will make you right.
I also suggest one of the enzyme based cleaners after the Premier. My favorites are the Mobil Fidelity Enzyme sold at Music Direct or Walker Audio.