What are some Anti-icing solutions for small planes without an on-board system?
There are many things you can do to mitigate the risk of icing, but most involve prevention via avoidance of icing conditions.  For example, getting a good weather brief, knowing where the freezing level is, staying away from visible moisture, and finally, recognition and taking evasive action.    

Pre-flight deicing liquids are not intended to prevent ice accumulation in flight.  As you noted, they will just blow off in the slip stream.  Anti-icing fluids such as TKS are very effective, but the aircraft must be equipped with a system to properly disperse it to be certified for flight into known icing conditions.

If you are not instrument rated it gets easier, because if you stay out of clouds you won’t ice up.  But if you want to fly IFR in the winter, (or any time you could be IFR in the  temperature zone where ice could form) your best method of increasing the safety margin is to arm yourself with knowledge, practice operational risk management, and exercise sound judgment to keep yourself out of icing.