You cannot totally get away from using ether in the process. Collodion is nitrated cotton (nitrocellulose) dissolved in a solution of diethyl ether and grain alcohol. Both ether and alcohol are needed to dissolve the nitrocellulose. Ether or alcohol alone won't do it. Commercial collodion already has ether in it.
You can substitute 190 proof grain alcohol or some brands of denatured alcohol for any additional ether called for in popular formulas for wetplate photography but, the properties of the working salted collodion will change to some degree. The changes may include longer setting times, different viscosity, texture, etc. Not necessarily bad changes, but different.