Common causes of slidejam include:
1. Slightly bent, bowed or otherwise deformed slides (SO calls them "runners") and/or channels. The runner is the center component between the outer channel (built in to the frame interior side) and the inner channel (built into the drawer exterior side). Eyeball sighting along the length of runner top and bottom often reveals obvious jam points. Straightening all three components usually requires good eyesight, patience and perseverance. Most can be straightened enough to enable drawer functionality, but severely mangled runners will require replacement.
2. Grime, grit and roach **** in the runners and channels. Degreaser, toothbrush, more patience and neck wrenching.
3. Corroded runners and channels. Burnishing wheel on the runners and small wire brush on the channels. Overnight Evaporust bath often works well on rusty runners.
After the runners and channels are straightened, cleaned, derusted and burnished, any lubricant is better than no lubricant. My personal choice is Sil-Glyde, a common brake lubricant. The NAPA brand is available in both a gel squeeze tube and an aerosol spray, and both are useful.