Explain how to filter Ca and Ba ions separately out of solution using insoluble compounds
You could carry out the standard qualitative analysis procedure. Dissolve the mixture in  hot acetic acid solution. 

Then add pottasium chromate ,barium is precipitated as its chromate salt(pale yellow ppt). 

Filter it and you could then precipitate Calcium from the resultant filtrate by adding ammonium oxalate.(precipitated as calcium oxalate, white ppt)