[linux-audio-user] LPs to CD - help with filters

I need some help understanding the basics of audio editing/filters using the linux tools. I've successfully used Broadcast2000 and SND to capture music input from cassette tape and LP, and have written some to CD. Next I want to do some work on the files, filter out what nasty stuff I can, but don't know what filters have what effect. I'm also not sure of the steps to think the process through; that is, if you see/hear symptom A, then X process, or X filter. Actually, I know how to apply the "plugins" in Broadcast 2000, but don't know what to pick or why. In SND I haven't gotten that far, but know it's possible. Any hints, howto suggestion or pointers would be GREATLY appreciated. My audio equipment is pretty modest; a SB16 ISA...and I know I might have to change that. Thanks in advance Reid