Those speakers are meant to be corner loaded, like K-Horns. Don't judge them until you position them properly.
The "paint spackling" looking stuff, in my experience, comes off very easily. I use a label protector, a spray on cleaner and a paint brush. I spray the cleaner, let it sit for a couple minutes, then brush in the direction of the grooves. Follow with a generous sink rinse and dry with a paper towel (or chamois if you prefer). I had a copy of "Live Stiffs" which went from unplayable to perfect after cleaning. Actually, it is hard to over estimate the importance of cleaning with collecting used records.
The Attic in Millvale sells paper sleeves (and plastic outer sleeves for that matter) for a dime each. Good quality, cheaper than the internet and it supports a local business. I try to always keep extras on hand.