Dipping produces lead acetate, a water-soluble lead compound that is toxic. It can be rendered LESS toxic, and much safer to handle, by precipitating out the lead into an insoluble lead salt.
Mix up about a pint of epsom salts. Make the solution saturated, i.e. add enough epsom salts so that no more will dissolve.
Take your used dip, and slowly add the epsom salts (magnesium sulfate) solution. You will immediately see solid lead sulfate fall out (precipitate) as a powder. Continue adding epsom salts until no more lead sulfate forms. If in doubt, add it all.
The solubility of lead acetate is about 50 grams per liter... that is a lot. Lead sulfate is only 0.0038 grams per liter. Lead sulfate is still toxic, like all lead salts, but much, much less dangerous than lead acetate.