I understand that in SEC, larger molecules or particles do not enter within in the pores and thereby elute faster with the void volume. However, there certainly have an upper limit of the particle size than can elute with the void volume, not get completely stuck due to their too big size.
In SEC, particles larger than the column’s pore size (typically up to ~30 nm) are excluded and elute at the void volume, but particles much bigger than the bead or column size cannot pass and may cause clogging. Thus, SEC effectively separates molecules up to a few tens of nanometers, with larger particles unsuitable for this method.
Abdelhak Maghchiche is right.
Before running size exclusion you should clarify your sample via low-speed centrifugation. If you plan use the column many times, you should filter your sample, typically on a 0.4 um acetate membrane.