Clear iPod Classic to delete old playlists?

i have an ipod classic. the majority of the music on it was downloaded using the old itunes program. i have playlists on the ipod that were created using itunes that i want to get rid of but can't now b/c music can't/won't access them. my question is: if i completely clear the ipod and then synch to upload all my music on my mac air, will i be able to delete those playlists? is it dangerous to do this? i'm just afraid of losing something or not being able to upload all the songs again. sorry if i'm not explaining this right.