Question
hi i have bought a second hand pond pump and filter how can i deep clean them so i don't transfer any viruses or bugs that might have been in the previous pond

Answer
Having them sit outside of the water for more than a few hours should kill any aquatic parasites, etc. that may have been in there.  Another option (and this would get it looking very clean, too) is to rub it with a cloth dampened with white vinegar.  It is highly acidic, but you won't have any problems as long as you thoroughly rinse it with water before placing it in the next pond.  For the filter, you may have to take it apart by removing some screws to access the inside better.