I think declaring it as a liquid is bound to cause issues, especially with Canadian customs. I always tag it as "body lotion" with a value of like $10 and it always gets through without any issues whatsoever. If what you're sending is in a small-ish package, then you could probably declare it as "used cosmetics".
You are getting good advice. "Liquids" raise a red flag. Cosmetic samples or something like that is a safer way to express it.
The other factor is that of time. In my experience, cross-border mailing is 2 to 3 times longer than usual. It can take three weeks for something to get to me.
Calling the package a "gift" of "used cosmetics" has always worked for me. 100+ packages in 4 years have all made it to me except 3. 2 were confiscated by USPS before making it to the border and 1 was confiscated by Singapore customs who then forwarded me the empty box LOL.
If it is really liquid-y and makes a sound, add a box of Tic Tacs