Effects are not stored nowhere - as dr.303 said you must resample them to save them for a later use.
Speaking about deleting parts. When you are recording pattern - when you hear the metronome and the screen shows pattern measure counting select part you want to delete something from and hit delete and hold pad of the sample you want to clear. This is hard if there are lots of different samples recorded on a track.
I usually use MICROSCOPE edit to remove notes. When you are in PATTERN mode hit F3 (MICRO) and press part number you want to clear. Now you should see all notes stored on this track. Just hit EVENT (if I'm correct it should be under F1) and press DELETE (F3) until there are no more notes in the list. Then hit EXIT and your track/part now is cleared.
Remember that MICRO edit is very powerful feature and you can also make beats only recording using the MICRO edit. But this is a different story. I really should make a video about this.
I will share my microscope knowledge here instead of make a new thread.
what i do is record fast notes as fast as they can quantize. then i delete the ones i dont want then i go into microscope and edit the velocitys to sound like drum rolls, can u post the numbers that mtach the beats >?