I've been into vinyl for than a year now, and have around 200 LPs (and a few 10" from the early 50s).
I used to use alcohol and a disc-washer style pad, that worked ok. It look clean when I was done, but I would play it, and everywhere it was played, dust and gunk would appear.
Then I discovered the soap and water method. You get a basin, put a dab of dish soap in, fill it with 4" of warm water. Put the LP in and move it around with the palms of your hand, so the entire surface gets wet. Now, take a take a record cleaning pad/brush, go clockwise on one side five times, then counter clockwise five times. Repeat for the other side.
Now pull the record out, and run it under tap water and turn it around to get all the soap off.
Get two towels or wash cloths and press against the label to get it dry, then dry off the surface and let it air dry somewhere.
I've washed all of my records this way, and have literally seen records that were white with mold become brand new in a matter of 30 seconds.
Depending on their condition, you can get a record fully "clean" and still have pops and clicks. I also have records that are clean, and have pretty much no clicks. It really all depends on the condition of the disc. Cleaning the record ensures that your only hearing the junk that's
on the record, not added junk on top of it.
You should also get a carbon fiber brush and use it upon playback to get any dust off.
Turntables don't usually cause pops and clicks.
I'd recommend you get a new cartridge or stylus. Worn out styli can really rip up your records. As for USB turntables, don't get one. Their crap. Besides, you can digitize with the stuff you have now. Just move the table and whatever you use for a phono stage (receiver?) to the computer. Get a RCA-1/8" connector, and connect the tape rec outputs to the computer's line in jack. Now get a free program called Audacity (audacity.sf.net), and your is business.
Btw, if you want a new table, get an old Dual, Thorens, Technics or something good off of e-bay. Their somewhere in the $100 range.
Also, check out your local thrift stores. I used to have a POS denon DP-26F table, and upgraded to a Realistic [Radio Shack] LAB-300 for $3.99, thanks to Goodwill.
Btw,
This is a clip of the aforementioned record that was caked white with mold, my aunt's copy of Chicago V. (most of the distortion you hear is a byproduct of their GE record changer)