Any toner that is designed for human hair is fine to use on locks. What usually causes residue is improper rinsing. So as long as you commit to rinsing until your water runoff is 100% (not 99%!) clear, then you’ll be fine!
“Residue free” products are designed to help minimize residue, but are not guaranteed to avoid residue. Everything is in the rinsing. Almost all shampoos, hair colors, and conditioners are A-okay to use on locks so long as you commit yourself to a rigorous rinse after each usage.