this is definitely the funniest query on here in a long time.(posted 8891 days ago)if i understand correctly, the liquid in a lavalamp is kerosene and, therefore, very oily. you'll probably want to wash your negatives in some sort of dish soap or something else that cuts through oily substances very well. if the dish soap won't work, try gojo or something like that. (i can't, of course, guarantee that gojo won't damage the emulsion. my father uses it to wash his work trucks, and it doesn't seem to affect the paint.)
good luck.