Ever wondered how to omit a particular part from your stamp for your desired effect?
Mask off the area of the stamp with sellotape or masking tape - needs to be medium tack to be effective. Ink the stamp as usual, carefully remove the sellotape/masking tape making sure your hands won't slip or ink transfer will mark your design and proceed to stamp your image.
If you need to use your Stamp-a-ma-jig for positioning purposes, ink your stamp as normal - including whole image of the stamp on to the Stamp-a-ma-jig plastic sheet. Clean and dry stamp as per normal routine and follow the 'masking' instructions above.