according to what I have read, hydrocarbons (wd-40) is fine to use on dyneema rope, the only problem is if it gets inside the strands and causes sand to stick to the rope that can cause wear. You are probably right wd-40 is fine.
HDPE is one of the hardest things to get anything to stick to. It is so nonreactive, that you could get rich figuring out a glue that would bond with it. This nonreactive property, along with UV resistance, is a primary reason that HPDE (actually UHMWPE) is so good for kite lines. Other "Super" materials just do not cut it on one property or the other.
So with a low potential for reaction with almost all chemicals, there may not be anything that you could put on your lines to harm them.
Here are some things that we use HDPE as a container for.
Muratic acid (hydrochloric acid)
The only issue on containers I have run into is using a lighter molecular weight (LDPE) material to contain wax remover. The wax remover seems to not attack the LDPE, but rather travel through it to the other side. That is evidenced by setting the wax remover container on top of a polycarbonate sheet, and over time, it melts the poly carbonate under the LDPE container. The control for this experiment is acetone which does not cause this reaction.