Just a note the chances the bias will stay as set when shipped is slim as the vibration and knocking around during shipping will most likely change the bias a small amount so always better to do it locally with a reputable tech if the amp is not easily user biased.
Using contact cleaner in tube sockets
My ARC VT100mkii which I just got, has a crackling from one of the channels. The tubes are new. When I first installed the tubes, it was fine. The following morning, I powered it on, and the crackling started. I swapped tubes with the other side and it was fine for a while. This evening, it started again. Will using contact cleaner damage the sockets? It is quick drying cleaner.