Acetone precipitation can be harsh to many proteins and you can end up with denatured protein that cannot be solubilized. Sonication might also denature your proteins. Run ultrafiltration or dialysis to remove your surfactants. 

Hi Samantha, water bath sonicators are relatively gentle compared to tip-ultrasonicators and I prefer using them to dissociate and dissolve protein aggregates.

You can do a quick test to see how to process your pellet in the sonicating waterbath. Make a BSA solution (with detergents) and precipitate it using acetone. 

Add PBS to the precipitate and see how the sonicating waterbath dissolves that pellet and apply that to your prep.

Solicitor are use to dissolve and dissociate. It will not help you. And probably, you denatured your protein or destroyed it by using acetone. Use detergents and then use a really small quantity of another solvent to precipitate it. 

Hi Samantha,

I use 100µl Ripa lysis buffer+EDTA free protease inhibitor to re-suspend the pellet. It works, if you see still some pellet left, it could be just contamination. By centrifugation you are able to just collect the supernatant and  discard the rest.

I used ultracentrifuge tubes(Amicon), it did not work for me.

Good luck,

Hi Samantha,

"TCA precipitation also gave high efficiency of protein recovery if prior sonication procedure was performed."

Article Comparison of protein precipitation methods for various rat ...

Fic et al. (2010) used an ultrasonic tip (Hielscher UP50H). I am working using a similar protocol, so I can confirm that it works.